Trigonometry - How To Solve Right Triangles

The Organic Chemistry Tutor
28 Jan 202010:16
EducationalLearning
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TLDRThis educational video script guides viewers on solving a unique right triangle problem involving two smaller triangles within a larger one. The goal is to determine the height 'h' of the larger triangle. Given a side length of 500 and angles of 30 and 60 degrees, the script uses trigonometric ratios, specifically tangent, to set up equations. By leveraging the properties of 30-60-90 triangles and algebraic manipulation, the video demonstrates how to isolate and solve for 'h'. The process involves finding the variable 'x' first, which represents the side adjacent to the 60-degree angle, and then using it to calculate 'h'. The video concludes with the exact and approximate values for 'h', emphasizing the importance of understanding trigonometric functions and algebra in solving geometric problems.

Takeaways
  • πŸ“š The video discusses solving a special case of right triangles involving two smaller triangles within a larger triangle.
  • πŸ“ The goal is to calculate the value of 'h', the height of the larger right triangle.
  • πŸ”’ Given measurements include a side length of 500 and angles of 30 and 60 degrees.
  • πŸ“ The speaker suggests labeling the sides and focusing on the small right triangle with a 60-degree angle.
  • 🧭 The trigonometric ratio 'tangent' is used to set up equations involving 'h' and 'x', the adjacent side to the 60-degree angle.
  • πŸ“‰ The tangent of 60 degrees is known to be root three, which simplifies the equation to h = root three times x.
  • πŸ” To find 'h', another equation involving 'h' and 'x' is needed, focusing on the larger right triangle with a 30-degree angle.
  • βž— The tangent of 30 degrees is found to be root three divided by three, which is used in the second equation.
  • βœ–οΈ Both sides of the second equation are manipulated to isolate 'h' and to set up an equation that can be solved for 'x'.
  • πŸ”’ Through algebraic manipulation, 'x' is found to be 250.
  • 🎯 With the value of 'x' known, 'h' can be calculated using the first equation, resulting in h = 250 times the square root of 3.
  • πŸ“ˆ The decimal approximation of 'h' is approximately 433.01, but the exact answer is 250 times the square root of 3.
Q & A
  • What is the main goal of the video?

    -The main goal of the video is to teach how to solve a special case of right triangles where two smaller triangles are within a larger triangle, with the objective of calculating the value of h.

  • What are the given measurements and angles in the problem?

    -The given measurements are a side length of 500 units, and the angles are 30 and 60 degrees.

  • What is the first step suggested in the video for solving the problem?

    -The first step suggested is to label the sides of the triangle, specifically labeling the side adjacent to the 60-degree angle as x.

  • What trigonometric ratios are mentioned in the video?

    -The trigonometric ratios mentioned in the video are sine (s), cosine (c), and tangent (t), which are part of the 'sohcahtoa' mnemonic.

  • What is the tangent of 60 degrees in the context of the video?

    -In the context of the video, the tangent of 60 degrees is equal to the square root of 3, which comes from the properties of a 30-60-90 triangle.

  • How does the video use the tangent of 60 degrees to form an equation?

    -The video uses the tangent of 60 degrees to form the equation: tangent of 60 degrees = opposite side (h) / adjacent side (x), which simplifies to √3 = h/x.

  • What is the second equation derived from focusing on the larger right triangle?

    -The second equation derived from the larger right triangle is: tangent of 30 degrees = opposite side (h) / adjacent side (x + 500), which simplifies to √3/3 = h/(x + 500).

  • What is the tangent of 30 degrees and how is it used in the video?

    -The tangent of 30 degrees is 1/√3, which is derived from the properties of a 30-60-90 triangle. It is used in the video to form an equation involving h and x + 500.

  • How does the video solve for x?

    -The video sets the two expressions for h equal to each other, resulting in an equation that, after simplification and algebraic manipulation, allows solving for x, which is found to be 250.

  • What is the final step to find the value of h?

    -The final step is to substitute the value of x (250) back into one of the earlier equations for h, which gives h = √3 * 250.

  • What is the approximate decimal value of h given in the video?

    -The approximate decimal value of h given in the video is approximately 433.01, which can be rounded to the nearest whole number.

Outlines
00:00
πŸ“š Introduction to Solving Right Triangles with Nested Triangles

The video begins by introducing a unique problem involving two right triangles within a larger triangle. The objective is to calculate the height 'h' of the larger triangle. Given a side length of 500 and angles of 30 and 60 degrees, the presenter suggests labeling the sides and focusing on the smaller triangle with a 60-degree angle. The trigonometric ratio of tangent is highlighted, with the tangent of 60 degrees being equal to the opposite side (h) over the adjacent side (x). The presenter uses the properties of a 30-60-90 triangle to establish that the tangent of 60 degrees is root three, leading to the equation h = root three times x. This equation is then set aside for further use.

05:01
πŸ” Using Trigonometry to Solve for 'h' in the Larger Triangle

Moving on to the larger triangle with a 30-degree angle, the presenter applies the tangent function again, setting up an equation involving h, x, and 500. The tangent of 30 degrees is derived from the properties of a 30-60-90 triangle, resulting in the equation h = (root three / 3) * (x + 500). To eliminate fractions and simplify the equation, both sides are multiplied by 3(x + 500), leading to a new equation that relates h to x and 500. The presenter then equates the two expressions for h, resulting in a linear equation in terms of x. Solving for x gives the value of 250, which is a crucial step towards finding the value of h.

10:03
🎯 Final Calculations and Conclusion

With the value of x determined to be 250, the presenter substitutes this value back into the earlier equation for h, yielding h = root three times 250. The presenter then calculates a decimal approximation of h, which is approximately 433.01, and suggests rounding to the nearest whole number for practical purposes. The video concludes with the exact answer for h being 250 times the square root of three, summarizing the process of solving a right triangle problem with nested triangles using trigonometric ratios and algebraic manipulation.

Mindmap
Keywords
πŸ’‘Right Triangle
A right triangle is a type of triangle that has one angle measuring exactly 90 degrees. In the context of the video, the main theme revolves around solving for unknown sides of right triangles using trigonometric ratios. The script discusses a larger right triangle containing two smaller right triangles, and the goal is to calculate the height 'h' of the larger triangle.
πŸ’‘Trigonometric Ratios
Trigonometric ratios are functions that relate the angles of a triangle to the lengths of its sides. In the video, the ratios sine (sin), cosine (cos), and tangent (tan) are mentioned as part of the 'sohcahtoa' mnemonic. These ratios are essential for solving right triangles, as they are used to establish equations involving the unknown height 'h' and side 'x'.
πŸ’‘Tangent (tan)
The tangent of an angle in a right triangle is the ratio of the length of the opposite side to the length of the adjacent side. The script specifically uses the tangent ratio to set up equations for the angles of 60 and 30 degrees. For example, tan(60Β°) is used to find the relationship between 'h' and 'x', and tan(30Β°) is used to relate 'h' to the sum of 'x' and 500.
πŸ’‘30-60-90 Triangle
A 30-60-90 triangle is a special type of right triangle where the angles are 30 degrees, 60 degrees, and 90 degrees. The sides are in the ratio of 1:√3:2. The script refers to this type of triangle to establish the tangent values for 60 and 30 degrees, which are √3 and 1/√3, respectively.
πŸ’‘Hypotenuse
The hypotenuse is the longest side of a right triangle, which is always opposite the right angle. In the video, it is mentioned that the hypotenuse is 'across the right angle'. The hypotenuse is not directly used in the equations, but understanding its position is crucial for visualizing the triangle and applying trigonometric ratios correctly.
πŸ’‘Adjacent Side
The adjacent side is the side of a right triangle that is next to a given angle, but not the hypotenuse. In the script, 'x' is labeled as the adjacent side to the 60-degree angle in the smaller right triangle and to the 30-degree angle in the larger right triangle. It plays a key role in the tangent equations set up to solve for 'h'.
πŸ’‘Opposite Side
The opposite side is the side of a right triangle that is across from a given angle and not adjacent to it. In the context of the video, 'h' is the opposite side to both the 60-degree and 30-degree angles in their respective triangles. The script uses the lengths of the opposite sides in the tangent equations to solve for 'h'.
πŸ’‘SOHCAHTOA
SOHCAHTOA is a mnemonic used to remember the trigonometric ratios sine, cosine, and tangent, which are essential for solving right triangles. The script uses this mnemonic to recall the tangent values for 60 and 30 degrees, which are critical for setting up the equations to find the value of 'h'.
πŸ’‘Equation
An equation is a mathematical statement that asserts the equality of two expressions. In the video, equations are formed using the tangent ratios to represent the relationships between the sides of the triangles. These equations are then manipulated to isolate and solve for the unknown variable 'h'.
πŸ’‘Variable
A variable is a symbol, often a letter, that stands for an unknown number or element in a mathematical problem. In the script, 'h' and 'x' are variables representing the unknown lengths of the sides of the triangles. The process of solving the problem involves finding the values of these variables using the given information and trigonometric ratios.
Highlights

Introduction to solving right triangles with a special case involving two smaller triangles within a larger triangle.

Objective to calculate the value of 'h' in the larger right triangle with given measurements.

Labeling the sides of the triangle for clarity and ease of calculation.

Focusing on the small right triangle with a 60-degree angle to establish the first equation.

Utilization of the trigonometric ratio tangent to set up the equation for the 60-degree angle.

Understanding the tangent of 60 degrees using the properties of a 30-60-90 triangle.

Deriving the equation h = √3 * x from the tangent of 60 degrees.

Shifting focus to the larger right triangle to find a second equation for 'h'.

Using tangent of 30 degrees to establish a relationship between 'h', 'x', and the adjacent side.

Calculating the tangent of 30 degrees and simplifying the equation.

Eliminating fractions by multiplying both sides of the equation by the adjacent side.

Setting the two expressions for 'h' equal to each other to solve for 'x'.

Solving the equation to find the value of 'x' as 250.

Substituting the value of 'x' back into the equation to calculate 'h'.

Final calculation of 'h' as 250 * √3, providing both an exact and approximate decimal value.

Conclusion on how to solve a right triangle problem involving two triangles within a larger triangle.

Transcripts
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