# Naming the Sides of a Right-Angled Triangle – 10th Class

A Right angled triangle △ABC is a triangle having one angle as 90°. If a right angled triangle having an angle as ϑ and other one is Φ=90°-ϑ.

Right angle: A right angle is equal to 90 degrees.

For Angle ϑ :

1. AB = Opposite side of angle ϑ = Perpendicular , we will call it as Perpendicular .
2. BC = Adjacent side of angle  ϑ = Base, We will name it as Base.
3. AC = Opposite side of right angle= hypotenuse (the longest side of a right-angled triangle, opposite the right angle.)

For Angle Φ :

1. AB = Adjacent side of angle Φ = Base, We will name it as Base.
2. BC = Opposite side of angle Φ = Perpendicular , we will call it as Perpendicular .
3. AC = Opposite side of right angle= hypotenuse (the longest side of a right-angled triangle, opposite the right angle.)

So if you noticed there is no change in hypotenuse , it is always AC because it is opposite to right angle and A triangle can have only one right angle , so hypotenuse will never change for same triangle.