Question

a rectangular is used for a gift. how much wrapping paper would it need if its dimensions are 8in by 4in by 5in?

Answer 1

A rectangular is used for a gift. How much wrapping paper would it need if its dimensions are 8in by 4in by 5in?

Solution:

We need to find the area of the lateral surface of the cuboid. The cuboid has six faces. They are pair wise equal. Thus we have

$$S = 2 (a h + a b + h b) (\text {s q u a r e i n c h e s})$$

So

$$S = 2 \cdot (8 \cdot 4 + 8 \cdot 5 + 4 \cdot 5) = 2 \cdot (3 2 + 4 0 + 2 0) = 1 8 4 (\text {s q u a r e i n c h e s})$$

Answer: 184 square inches of wrapping paper