# Two corresponding sides of two similar triangles are 6cm and 14cm. If the perimeter of the first triangle is 21cm, how do you find the perimeter of the second triangle?

Mar 19, 2016

The perimeter of the second triangle is 49cm

#### Explanation:

because the two triangles are similar their corresponding lengths will be in the same ratio
So
Side 1 divided by side 2 = perimeter 1 divided by perimeter 2
and thus if the unknown perimeter is x then
$\frac{6}{14}$ =$\frac{21}{x}$
and $6 x$ = $21 \times 14$
$x$ = $\frac{21 \times 14}{6}$ = 49
So the perimeter of the second triangle is 49cm