Question Video: Using Right Triangle Trigonometry to Find an Unknown Angle | Nagwa Question Video: Using Right Triangle Trigonometry to Find an Unknown Angle | Nagwa

# Question Video: Using Right Triangle Trigonometry to Find an Unknown Angle Mathematics • First Year of Secondary School

## Join Nagwa Classes

In the given figure, find the measure of angle π, in degrees, to two decimal places.

01:36

### Video Transcript

In the given figure, find the measure of angle π in degrees to two decimal places.

In order to solve this problem, weβre going to have to use the sine, cosine, and tangent trigonometrical ratios. sin π is equal to the opposite divided by the hypotenuse, cos π is equal to the adjacent divided by the hypotenuse, and tan π is equal to the opposite divided by the adjacent.

In order to decide which ratio to use, we need to label the sides of our triangle. The longest side β the one opposite the right angle β is the hypotenuse. The side labelled five is the opposite as it is opposite the angle π. And the third side is called the adjacent as it is next to or adjacent to the angle π. As the opposite is equal to five and the hypotenuse is equal to 11, we will use the sine ratio. sin π is equal to five divided by 11.

In order to calculate the angle π, we need to use the inverse sine operation. Therefore, π is equal to inverse sine of five 11ths. Typing this into our calculator gives us an answer of π equals 27.04 degrees to two decimal places. Therefore, the measure of the angle π is 27.04.

## Join Nagwa Classes

Attend live sessions on Nagwa Classes to boost your learning with guidance and advice from an expert teacher!

• Interactive Sessions
• Chat & Messaging
• Realistic Exam Questions