What is the x and What is the perimeter?

Pythagorean theorem: a^2 + b^2 = c^2

the top triangle:
a^2 + 10^2 = 18^2 (the bottom side=10 bc of the rectangle, equal sides)
a^2 + 100 = 324
a^2 = 224
a= 14.97... lets round it to 15 lol
so now we just found the left side for the top triangle

triangle to the farthest right:
2^2 + b^2 = 5^2
4 + b^2 = 25
b^2 = 25 -4
b^2 = 21
b = 4.58.. I’ll round it to 4.6 since it says to round it to the nearest tenth in the question
- we just found the left side for that triangle & that would also be the side for the rectangle’s height.

15 + 4.6 = 19.6

Are you asking for 6 or 15?