trig
posted by maranade .
ABC with angles AB, and C and sides AB,BC, and AC, angle B is right 90degree angle, if sin of angle A is 0.5, side BC 8in., what is length of AC

Perhaps you recognized the 30690 triangle (sinØ=1/2 , so Ø=30°)
so just use a simple ratio:
h/2 = 8/1
h = 16
or
sinØ  .5
Ø = 30°
then sin30 = 8/h
h = 8/sin30 = 8/(1/2) = 16