Mathematics for IGCSE & O level - Mensuration (Section 10 - No. 22)
Calculate the base area of a cone with slant height 8.5cm and curved surface area 50 cm².
19.0 cm²
18.8 cm²
17.9 cm²
18.0 cm²
説明
Curved surface area = πrl, 50 = π * r * 8.5, r = 1.87cm, Area of base = πr² = 10.97cm²