Question

In PQR, sin P =2/5, sin R = 1/2,and p= 8. Find the side length r.

Answer 1

We need to use the law of sines

sin P sin Q sin R

-------- = ------- = --------

p q r

The capital letters are the angles and the lower case are the side lengths

We know sin P and sin R and p

sin P sin R

-------- = --------

p r

2/5 1/2

------ = --------

8 r

Using cross products

2/5 r = 1/2 (8)

2/5 r = 4

r = 4 * 5/2

r = 10