Which equation can be used to find x, the length of the hypotenuse of the right triangle? A triangle has side lengths 18, 24, x.
18 + 24 = x
18 squared + 24 = x
(18 + 24)² = x²
18²+ 24² = x²

Solution:

Consider a right angled triangle with sides AB = a, BC = b and AC = c as shown below.

For a right angled triangle the Pythagoras theorem is applicable which states:

AC² = AB² + BC²

c² = a² + b²

So if the sides of a right angled triangle 18, 24 and x then the possible equations to find x are :

24² = 18² + x² 

Or

x² = 18² + 24²

However the x is given as the length of the hypotenuse, therefore the relationship used to find x will be:

x² = 18² + 24²

Which equation can be used to find x, the length of the hypotenuse of the right triangle? A triangle has side lengths 18, 24, x.

Summary:

The equation that can be used to find x, the length of the hypotenuse of the right triangle if the triangle has side lengths 18, 24, x is 18²+ 24² = x².