# explain pythagoras theorem and give 1 example

Hi!

Here is the answer to your query.

Pythagoras Theorem:

**In a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides of the triangle.**

In a right triangle, side opposite to the 90° is always the hypotenuse.

∆ABC is a right triangle, right angled at B.

∴ AC

^{2}= AB^{2}+ BC^{2}(Pythagoras Theorem)**Example**:

ΔABC is a right triangle right angled at B. If AC = 25 cm and AB = 15 cm, then find the side BC.

ΔABC is a right-angled triangle, right-angled at B.

∴AC

^{2 }= AB^{2 }+ BC^{2 }(Pythagoras theorem)⇒15

^{2}+ BC^{2 }= 25^{2}⇒BC

^{2}= 25^{2}− 15^{2}⇒BC

^{2 }= 625 − 225⇒BC

^{2 }= 400⇒BC

^{2 }= 20^{2}∴ BC = 20 cm

Cheers!

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