The perimeter is the sum of all of the lengths of the sides. To find the perimeter, add together the length of each side.
For this triangle, our side lengths are 7, 7, and 9.
7 + 7 = 14
14 + 9 = 23
The perimeter of a triangle that has two sides measuring 7 centimeters and a third side measuring 9 centimeters is 23 centimeters.
Hope this helps!! :)