Question

7.8 cm

12 cm

8 cm , 10 cm,

10 cm

O

8 cm

Which of the following is the lateral surface area of the triangular prism represented with a net?

(1 point)

253.6 cm2

Answer 1

I can help — but I need one clarification from the net: which number is the prism length (the distance between the triangular bases)? In a triangular prism net the three rectangles have widths equal to the three side lengths of the triangular base and height equal to the prism length. So

Lateral surface area = perimeter of base × prism length = (a + b + c) × h.

From the numbers you typed I see 7.8, 8, 10, 10, 12, 8 — but it’s not clear which three are the triangle sides and which is the prism length. Here are a few possible interpretations:

- If the triangle sides are 7.8, 8, 10 and the prism length is 12:
LSA = 12 × (7.8 + 8 + 10) = 12 × 25.8 = 309.6 cm².

- If the triangle sides are 7.8, 10, 10 and the prism length is 8:
LSA = 8 × (7.8 + 10 + 10) = 8 × 27.8 = 222.4 cm².

- If the triangle sides are 7.8, 8, 10 and the prism length is 10:
LSA = 10 × 25.8 = 258.0 cm².

None of these give 253.6 cm², so 253.6 is unlikely to be correct for the usual net interpretation. Send a clear picture of the net or tell me exactly which number labels the three base edges and which is the prism length, and I’ll compute the exact lateral surface area.