Answer:
b = 36
Step-by-step explanation:
Assuming this is a right triangle with hypotenuse = c and legs a and b
Then using Pythagoras' identity.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
a² + b² = c², and substituting values
15² + b² = 39², that is
225 + b² = 1521 ( subtract 225 from both sides )
b² = 1296 ( take the square root of both sides )
b = [tex]\sqrt{1296}[/tex] = 36
