Lessons > law of sines
> quiz - law of sines
question 1 of 10
10 points
in aabc, mza=15°, a = 10, and b=11. find c to the nearest fenth.
b

50-60=10

step-by-step explanation:

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x