Answer: d) 58
Step-by-step explanation:
As it is a right triangle, we need to use Pythagoras' Theorem.
The x (because it is the largest side and it is opposite to the right angle), is the hypotenuse and the other sides are 42 and 40.
The theorem says the square of the hypotenuse is equal to the sum of the squares of the other two sides.
hyp² = side² + other side²
h² = a² + b²
In our case:
x² = 40² + 42²
x² = 1600 + 1764
x² = 3364
x = √3364 = 58