Answer:
75 cm
Explanation:
The diagonal d divides the rectangle into 2 right triangles with d as the hypotenuse.
Using the right triangle formed on the left and using Pythagoras' identity.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
d² = 45² + 60² = 2025 + 3600 = 5625 ( take square root of both sides )
d = 75
The diagonal is 75 cm