The sun is passing directly over an 80ft. tall building. The shadow is 60ft. long when the angle (theta) that the sun makes with level ground is increasing at the rate of .327 radians per minute. At what rate is the shadow decreasing. (express your answer in inches per minute, to the nearest tenth of an inch.)

Question

PLEASE HELP. I AM EXTREMELY CONFUSED.

Answer 1

tantheta=distance/80

take the derivative of each side...

sec^2 Theta dTheta/dt=dx/dt *1/80

Solve for dx/dt

figure the triangle first: 60-80-100
sec Theta=60/100

and you have it.
check my work.