Answer:
eqn : 9 x 9 x h = 1620
h = 1620 / 81 = 20
Step-by-step explanation:
X=7.5 area= 42
You know that the total perimeter is 39 so to find x you need to add what you already have. You’ll find there are 3 sides you don’t know the length of and all you have to do is find the shorter one which is basically 9-7=2 then add everything together and subtract it from 39 then divide it by 2 to find the two sides left
Answer:

Step-by-step explanation:
As the triangles are similar :
45/55 = (12x - 3)/143
9/11 = (12x - 3)/143
9 x 13 = 12x - 3
12x = 117 + 3
12x = 120
x = 10