Question

Which expression helps you find the length x of a side of a rectangle that has a diagonal of 15 units and a width of 9 units?

Answer 1

15²-9²= x² use Pythagoras' theorum and square the two smaller sides to get the square of the hypotenuse (the diagonal) then rearrange this to get the above calculation

Answer 2

The diagonal of rectangle is 15 units and a width is 9 units.

Let the length of rectangle is x units.

Relation of sides of rectangle and diagonal

Sum of square of length of side of rectangle is equal to square of length of diagonal.

Using pythagoreous theorem:

$x^2+9^2=15^2$

$x^2=15^2-9^2$

$x^2=(15+9)(15-9)$

$x^2=24\times 6$

$x^2=144$

$x=\sqrt{144}$

$x=12$

Above all are possible expressions to find x.