Question

the hypoteenuse of a right angled triangle is 25 cm. if one of the remaining two sides is 15 cm, find the lenght of its third side.

Answer 1

Hypotenuse = 25cm

Second side = 15cm

For this question, use the Pythagoras Theorem:

(Hypotenuse)² = (Second side)² + (Third side)²

Twist the formula so that (Third side)² = (Hypotenuse)² - (Second side)².

Now, substitute the given values into the formula.

(Third side)² = (25²)cm - (15²)cm

Evaluate the powers of 25 and 15.

(Third side)² = 625cm - 225cm

Subtract 225cm from 625cm.

(Third side)² = 400cm

Square root both sides of the equation to remove the power of the unknown side.

Third side = √400cm

Then, evaluate the square root of 400cm.

Third side = 20cm

∴ Hence, the third side is 20cm.