Question

Suatu kerucut memiliki volume 1884 cm^ jika tingginya 8 cm tentukan
a.panjang jari jari kerucut
b.panjang garis pelukis
c.luas selimut kerucut
d.luas permukaan kerucut

Tolong yea,pke cara

Answer 1

Vol = 1884 cm³
t = 8 cm
vol = 1/3 . La . t
1884 = 1/3 . 22/7 . r² . 8
r² = (1884 × 3×7) ÷ (1×22×8)
r² = 39.564 ÷ 176
r = √ 225 = 15cm
s = √t² + r²
s = √ 8² + 15²
s = √ 64 + 225
s = √ 289 = 17cm
Ls = phi . r . s
= 3,14 . 15 . 17 = 800,7 cm²
Lp = phi . r (r + s)
= 3,14 . 15 (15 + 17)
= 1507,2 cm²