Question

If a square mirror has a 30-inch diagonal, what is the area of the mirror, in inches

Answer 1

You can find the length of a side by using the Pythagoras theorem
Let x be length of each side then:-
2x^2 = 30^2
x^2 = 900/2 = 450
area  = length of one side squared:-
area = x^2 = 450 ins^2  <---- Answer