Question

A rectangular book measures 3 x 5. What is the length of its
diagonal?

Answer 1

let's pythagorean theorem!
a^2 + b^2 = c^2
a and b are the sides, c is the diagonal
3^2 + 5^2 = c^2
9 + 25 = c^2
34 = c^2
5.83 = c