The perimeter of an isosceles triangle can be found by adding the length of its three sides. An isosceles triangle is a triangle with two equal sides and two equal angles.

One real-life example of an isosceles triangle is the roof of a house. The two sides of the roof that slope down from the peak are often equal in length, making the roof an isosceles triangle. The perimeter of the roof would be the sum of the three sides, which could be used to determine the amount of materials needed for construction or repairs.

Another example of an isosceles triangle can be found in musical instruments such as the violin or guitar. The top of these instruments is often shaped like an isosceles triangle, with two sides being equal in length and forming an angle at the top. The perimeter of this triangle would be the sum of the three sides, which could be used to determine the length of material needed to construct the instrument's top.

The formula for determining the perimeter of an isosceles triangle is defined as: