Isoceles Triangle

Isosceles triangle is a triangle where

• Two sides are equal
• Angles opposite to equal sides are equal

Here,

• a is the side which is equal, AB = AC
• b is the base, BC = b
• Angles opposite to equal sides are equal, ∠B = ∠C ( Check Proof )

Perimeter

Perimeter of isosceles triangle = Sum of all sides

= a + a + b

= 2a + b

Perimeter of isosceles triangle = 2a + b

Properties of Isosceles triangle

• Two sides are equal
• Angles opposite to equal sides are equal
• Altitude is the median

∴ AD ⊥ BC

& D is the mid – point of BC