121k views
1 vote
Use the special triangle shown on the unit circle to find the sine of π/3.

Use the special triangle shown on the unit circle to find the sine of π/3.-example-1
User Eli Arbel
by
6.5k points

1 Answer

5 votes

Answer:

D) (√3)/2

Explanation:

The sine of an angle is the y-coordinate of the point where the terminal ray intersects the unit circle. The diagram shows that to be (√3)/2.

___

SOH CAH TOA reminds you that ...

Sin = Opposite/Hypotenuse

For the angle of interest, the hypotenuse is 1 (the radius of the unit circle), and the opposite side is the y-coordinate of the point on the unit circle, (√3)/2. Hence, ...

sin(π/3) = (√3)/2

_____

Comment on unit circle

If you remember that the sine of an angle is the y-coordinate, and the cosine of an angle is the x-coordinate on the unit circle, it can help in many problems—especially ones where you're concerned with trig values in different quadrants, and when you get into polar coordinates and translating back and forth to rectangular coordinates.

User Bimalesh Jha
by
6.4k points