The surface area of the pyramids are ;
1. 625ft²
2. 72ft²
3. 178cm²
4. 4380m²
The surface area of a regular triangular prism is calculated as;
SA = area of base + 4 × area of triangle
1. area of base = 25 × 25
= 625ft²
area of triangle = 1/2 × 25 × 32
= 25 × 16 = 400
SA = 625 + 4 × 400
SA = 625 + 1600
SA = 2,225 ft²
2. area of base = 4² = 16ft²
area of triangle = 1/2 × 4 × 7
= 14
SA = 16 + 4× 4
= 16 + 56
= 72 ft²
3. Area of base = 10 × 8
= 80 cm²
area of triangle = 1/2 × 6 × 8
= 24 cm²
area of triangle = 1/2 × 5 × 10
= 25 cm²
SA = 80 + 2 × 25 × 2 × 24
= 80 + 50 + 48
= 178 cm²
4. Area of base = 60 × 30
= 1800m²
area of triangle = 1/2 × 60 × 25
= 750m²
area of triangle = 1/2 × 30 × 36
= 540m²
SA = 1800 + 2 × 750 + 2 × 540
= 1800 + 1500 + 1080
= 4380m²