Answer:
108 cm²
Explanation:
the surface area is the sum of all individual shapes areas on the surface.
2 right-angled triangles
3 rectangles
area of a right-angled triangle is At = a×b/2
At = 4×3/2 = 6 cm²
we need it twice : 12 cm²
one rectangle (length×width) = 8×3 = 24 cm²
one rectangle = 8×4 = 32 in²
one rectangle = 8×5 = 40 cm²
total surface area
A = 12+24+32+40 = 108 cm²
an area is always a square unit (power of 2).
a volume is always a cubic unit (power of 3).
and a length is always a simple unit (power of 1).