Answer: 20 cm².
- A 40 cm²
- B 20 cm²
- C 13 cm²
- D 25 cm²
Correct answer: B. 20 cm²
Explanation: Area = (1/2) × base × height = (1/2) × 8 × 5 = 20 cm².
Three standard 3D solids and their key formulas: a cylinder's volume scales with the full height, a cone's volume is exactly one-third of the cylinder with the same base and height, and a sphere's volume and surface area both follow distinct r-based formulas worth memorising separately.
Concept context
Perimeters, areas, and volumes of 2D and 3D shapes