Question

Hitunglah luas permukaan bangun ruang berikut. (Nomor b dan c).

Tolong jawab pake cara ya.

Answer 1

B.
r bola = r kerucut = 7
t kerucut = 24
S kerucut = √t²+r² = √(24²+7²)= 25
luas permukaan bangun = luas 1/2 bola + luas selimut
L = 2 π r² + π r s
L = π r ( 2r + s)
L = ²²/₇ (7)(14+25)
L = 22 (39) = 858  cm²

c.
rbola = r tab = r kerucut = 1/2(8) = 4
t tab = t₁ = 16
s kerucut = 5

Luas permukaan bangun = luas 1/2 bola + luas selimut tab+ luas selimut kerucut

L = 2πr²+ 2 π r t₁ + π r s
L = π r ( 2r + 2t₁ + s)
L = (3,14)(4)(8+ 32+5)
L = 12,56 (45) = 565,2 cm²