Types of Triangles: Applying the formula

Look at the isosceles triangle below:

What is its perimeter?

Since we are referring to an isosceles triangle, the two legs are equal to each other.

In the drawing, they give us the base which is equal to 4 and one side is equal to 6, therefore the other side is also equal to 6.

The perimeter of the triangle is equal to the sum of the sides and therefore:

$6+6+4=12+4=16$

16

The two legs of the triangle are equal. Calculate the perimeter of the triangle.

Since the two legs are equal, we can claim that:

$AB=AC=9$

The perimeter of the triangle is equal to the sum of all sides, meaning:

$AB+AC+BC$

Let's substitute the known data and calculate the perimeter:

$9+9+3=18+3=21$

21

What is the perimeter of the given isosceles triangle?

Due to the fact that the the triangle is isosceles, its two legs are equal to one another.

Therefore, the base is 7 and the other two sides are 12.

The perimeter of a triangle is equal to the sum of all the sides together:

$12+12+7=24+7=31$

31

Given an equilateral triangle:

What is its perimeter?

Since the triangle is equilateral, that is, all sides are equal to each other.

The perimeter of the triangle is equal to the sum of all sides together, the perimeter of the triangle in the drawing is equal to:

$5+5+5=15$

15

All of the sides of the triangle are equal. Calculate the perimeter of the triangle.

21

In the triangle ABC, the two legs are equal in length. Calculate the perimeter of the triangle.

16

The three sides of the triangle ABC are equal. Calculate the perimeter of the triangle.

15