The coordinates of a are (0,4) and the x-coordinate of b is 5. what is the y-coordinate of b if ab=13? (two answers are possible.)

*could you give an explanation, i don't understand it but i know the possible answers which are 16 or -8*

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,