Answer:
20
Step-by-step explanation:
Since this is a right triangle, we can use the Pythagorean theorem
a^2 + b^2 = c^2, where a and b are the sides and c is the hypotenuse
15^2 + b^2 = 25^2
225 + b^2 = 625
b^2 = 625 -225
b^2 =400
Take the square root of each side
sqrt(b^2) = sqrt(400)
b = 20
