Which equation models T as a function of h?

Question

The length T of a shadow cast by a tree on a sunny day varies directly as the height H of the tree. A tree 72 inches tall casts a shadow 81 inches long. Which equation models T as a function of h?

Answer 1

Assuming that the position of the sun is not moving in this problem, then the height to length ratio must remain constant.

 

T/H = 81/72 = 9/8

 

so...

 

T = H*9/8