Given :
The shadow of the tree = 25 feet from the top of the tree to the ground
the distance from the base of the tree to tip of its shadow is 15 feet
Let the height of the tree = x
So, 25 , 15 and x are forming a right angle triangle
25 is the hypotenuse of the triangle ,
x and 15 are the legs of the triangle
WE will find x using Pythagorean theorem
So,
So, the height of the tree = 20 feet
The answer is option A. 20 feet