Question

1. find the surface area of the prism. (options: 156 cm², 96 cm², 90 cm², 150 cm²) image of a triangular prism with dimensions 3 cm, 4 cm, 5 cm, 12 cm

Explanation:

Step1: Calculate base triangle area

The base is a right triangle with legs 3 cm and 4 cm. Area = $\frac{1}{2} \times 3 \times 4 = 6$ cm². Two bases: $2 \times 6 = 12$ cm².

Step2: Calculate perimeter of base triangle

Perimeter = $3 + 4 + 5 = 12$ cm.

Step3: Calculate lateral surface area

Lateral surface area = perimeter × length = $12 \times 12 = 144$ cm².

Step4: Total surface area

Total = lateral + 2×base = $144 + 12 = 156$ cm².

Answer:

156 cm²