Calculate Isosceles Triangle Perimeter with Side Lengths 9 and 3

Question

The two legs of the triangle are equal.

Calculate the perimeter of the triangle.

00:00 Find the perimeter of the triangle

00:03 Equal sides according to the given data

00:07 The triangle's perimeter equals the sum of its sides

00:13 Let's substitute the side values and solve for the perimeter

00:19 And this is the solution to the question

Since the two legs are equal, we know that:

$AB=AC=9$

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

$AB+AC+BC$

Now let's substitute the known data into the formula and calculate:

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