Carilah LP kerucut
r: 12
s: 21
》Bangun Ruang
= πr² + πrs
= π × 12 × 12 + π × 12 × 21
= π × 144 + π × 252
- = 144π + 252π
- = 396π cm²
- = 1.243,44 cm²
LP = phi × r × (s + r)
LP = 3,14 × 12 × (21 + 12)
LP = 3,14 × 12 × (33)
LP = 3,14 × 12 × 33
LP = 3,14 × 396
LP = 1.243,44
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Jadi, Luas permukaan kerucut tersebut adalah 1.243,44