Answer:
535.2 cm²
Explanation:
The surface area the solid formed by the net in exercise 4 can be calculated by finding the area of each part that makes up the net.
The net consists of 2 triangles and 3 rectangles.
Each triangle has a base (b) of 8 cm and a height (h) of = √(8² - 4²) (using Pythagorean theorem)
height = 6.9cm
Each rectangle has length (l) of 20cm, and width (w) of 8cm
Therefore, Surface Area (S.A) = area of 3 rectangles + area of 2 triangles
S.A = 3(l*b) + 2(½*b*h)
S.A = 3(20*8) + 2(½*8*6.9)
S.A = 3(160) + (1*8*6.9)
S.A = 480 + 55.2 = 535.2 cm²