Hello,
Let's assume n the number searched.
nine less 3 times n is written 9-3n
Please insert your equation number
I think the answer would be 38in^2
Because the equation is : (a+b) *h / 2
A and b are both the bases of the trapezium
So (11 + 8) these are the bases and the height is 4 so you would do
(11+8)*4 / 2
(19)*4 / 2
76 / 2
= 38
The answer would be 21 because its the same length as the other side.