Answer:
1222
Step-by-step explanation:
You have a triangular prism on top of a rectangular prism. The surface area is the sum of the areas of the exposed faces.
Starting with the triangular prism, the surface area is the area of the two triangular bases plus the area of the two rectangular sides (the bottom rectangular face is ignored).
A = ½ (10) (12) + ½ (10) (12) + (13) (9) + (13) (9)
A = 60 + 60 + 117 + 117
A = 354
The surface area of the rectangular prism is the area of the two rectangular bases (front and back), plus the two walls (left and right), plus the bottom, plus the top (minus the intersection with the top prism).
A = (19) (11) + (19) (11) + (9) (11) + (9) (11) + (19) (9) + (19) (9) − (10) (9)
A = 209 + 209 + 99 + 99 + 171 + 171 − 90
A = 868
So the total surface area is:
354 + 868
1222
You'll have to multiply 0.7 by 120.
120*0.7 = n
n is the number that is 70% of 120
120 * 0.7 = 84
Hope this helps :)
