Answer:
Option D. 15m
Explanation:
In the given right triangle b is the unknown leg.
we have to find the value of b.
By Pythagoras theorem in a right angle triangle
Hypotenuse² = Base² + Height²
25² = 20² + b²
625 = 400 + b²
b² = 625 - 400
b² = 225
b = √225
b = 15 m
Option D. 15m is the answer.