# Obtuse angles and the unit circle.

- Author:
- Callum Marshall, Jim Voss

- Topic:
- Angles, Circle, Unit Circle

Move the slider to change the size of the angle marked as theta in the semicircle shown below.

## Question 1

a. Find an obtuse angle with the same sine as sin(40).
b. Find an obtuse angle with the same sine as sin(10).
c. Find an acute angle with the same sine as sin(150).
d. Find an acute angle with the same sine as sin(160)
What's the relationship between the sine of an angle and its supplement; and ?

## Question 2

Find
b.
c.
d.

**TWO**angles for; a.## Question 3

How would you describe the relationship between the cosine of an angle, and the cosine of its supplement, ?