Answer: 24 
Step-by-step explanation:
A=1/2hb
to find lenth of triangle: the side of the square is 10 and on the top, the triangle takes up 10-6 in so it must be 4 in long
to find height, it is 16-10 in of of the square. so itmust be 6 in
so to find area:
A=1/2*6*4
= 1/2*24
=24
So for this, multiply both sides by 9, and your answer will be:

You can use a system of equations to solve this problem. Let one equation be the sum of the sides and the other equation be the difference of the equations. Using elimination method you get 4 & 14.
4+14=18
14-4=10
(6×5)×10=300 Since 6×5=30×10=300