Similar Triangles Perimeter Problem: Calculate Using 3.5, 1.5, and 4 Units

Question

The triangles above are similar.

Calculate the perimeter of the larger triangle.

00:00 Find the perimeter of the second triangle

00:03 The triangle's perimeter equals the sum of its sides

00:10 This is triangle 1's perimeter

00:15 Similar triangles according to given data

00:21 The ratio of triangles' perimeters equals the similarity ratio

00:26 Let's substitute appropriate values and solve for the perimeter

00:32 Let's isolate P2

00:46 Let's substitute perimeter 1's value

00:53 And this is the solution to the question

We calculate the perimeter of the smaller triangle (top):

$3.5+1.5+4=9$

Due to their similarity, the ratio between the sides of the triangles is equal to the ratio between the perimeters of the triangles.

We will identify the perimeter of the large triangle using $x$ :

$\frac{x}{9}=\frac{14}{3.5}$

$3.5x=14\times9$

$3.5x=126$

$x=36$