Right Triangle Trigonometry Exercise 1

Reference Triangle
Reference Triangle

Instructions for Exercise 1

Here is the first of three examples. Use the triangle to the right for reference. The solution is at the bottom of the post. A trig table and the trig wheels are also included.

Angle 2 is 50°.

The length of Side B (the hypotenuse) is 40.

Find the length of sides A and C, and angle 1.

Trig Wheels

Trig Wheels
Trig Wheels

Solution for Exercise 1

This solution demonstrates one of a number of possible ways to come to the values in bold; the important thing is to arrive at the same values shown for each unknown.

Angle 2 is 50°. The length of Side B (the hypotenuse) is 40. Find the length of sides A and C, and angle 1.

Angle 1 can be found by subtracting 50° from 90°. Angle 1 is 40°.

Since side A is opposite angle 2, it can be found by multipying the sine of 50°, 0.7660 as found in the table, by the hypotenuse, 40. The length of side A is 40 x 0.7660, or 30.64

Adjacent side C can be found by multiplying the cosine of 50°, 0.6428 as found in the table, by the hypotenuse, 40. The length of side C is 40 x 0.6428, or 25.71.

Click on the trig table to see it full size

Trig Table
Trig Table

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Comments 1 comment

emather 7 years ago from United Arab Emirates

great hub. nice to see somebody interested in math like me

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