Jawaban:

Diketahui:

• r kerucut = 30 cm
• s kerucut = 50 cm

Ditanya:

• tinggi kerucut?
• volume?
• luas selimut
• luas permukaan

Jawab:

a) Tinggi kerucut

t = √s² - r²

= √(50 cm)² - (30 cm)²

= √2.500 cm² - 900 cm²

= √1.600 cm²

= 40 cm

b) Volume kerucut

V = ⅓ × La × t

= ⅓ × π × r² × t

= ⅓ × 3,14 × (30 cm)² × 40 cm

= ⅓ × 3,14 × 900 cm² × 40 cm

= 37.680 cm³

c) Luas selimut kerucut

Ls = π × r × s

= 3,14 × 30 cm × 40 cm

= 3.768 cm²

d) Luas permukaan kerucut

LP = Luas alas + Luas selimut

= (π × r²) + 3.768 cm²

= (3,14 × (30 cm)²) + 3.768 cm²

= 2.826 cm² + 3.768 cm²

= 6.594 cm²