Concise Selina Solutions for Class 9 maths Chapter 13 Pythagorean Theorem


Pythagorean Theorem, the well-known geometric theorem that the sum of the squares on the legs of a right triangle is equal to the square on the hypotenuse (the side opposite the right angle) - or, in familiar algebraic notation, a2 + b2 = c2. Pythagoras theorem states that “In a right-angled triangle, the square of the hypotenuse side is equal to the sum of squares of the other two sides“. The sides of this triangle have been named as Perpendicular, Base and Hypotenuse. Here, the hypotenuse is the longest side, as it is opposite to the angle 90°. The Pythagorean Theorem is used any time we have a right triangle, we know the length of two sides, and we want to find the third side. For example, I was in the furniture store the other day and saw a nice entertainment centre on sale at a good price. The Pythagorean Theorem was one of the earliest theorems known to ancient civilizations. This famous theorem is named for the Greek mathematician and philosopher, Pythagoras. According to legend, Pythagoras was so happy when he discovered the Theorem that he offered a sacrifice of oxen.

This simple but powerful equation can help us gain confidence in manipulating numbers with exponents. And because right triangles are so common, it will help us understand how useful it is to be comfortable with exponential terms.