posted by rick .
If sin = 4/5 with A in QII, and sin B = -3/5 with B in QIV find cos(A-B)
If sinA = 4/5 in QII
draw you triangle in QII, and find the third side.
The third side is 3. (Do the same thing for sin B= -3/5
53. the longest side is 55 cm. find the length of the shortest side