Question

The perimeters of the triangles shown below are equal

Answer 1

Answer:

$x=19$

Step-by-step explanation:

The perimeter of a shape is the sum of all of its side lengths. Therefore, the perimeter of the first triangle is $x-7+x-7+x-7=3x-21$ and the perimeter of the second triangle is $9+15+12=36$.

We are given that the perimeters of the triangles are equal, so $3x-21$ equals $36$. As an equation, that would be $3x-21=36$. Solving for $x$, we get:

$3x-21=36$

$3x=57$ (Add $21$ to both sides of the equation to isolate $x$)

$x=19$ (Divide both sides of the equation by $3$ to get rid of $x$'s coefficient)

Hope this helps!

Answer 2

Answer:

x=19

Step-by-step explanation:

The perimeter of the right triangle is

P=9+12+15 =36

The perimeter of the left triangle is

P =x-7+ x-7+ x-7 = 3x-21

Set them equal

36 = 3x-21

Add 21 to each side

36+21 = 3x-21+21

57 = 3x

Divide each side by 3

57/3 = 3x/3

19 =x