Question

Luas permukaan tabung tanpa tutup 1.570 cm. Jika
Tinggi tabung 20 cm, volume tabung.....
a.2680 c.6280
b.4280 d.8260

Answer 1

Luas tabung tanpa tutup = 1570 cm²
t = 20 cm
V =...?

L = π . r (r + 2t)
1570 = 3,14 * r (r + 2 * 20)
1570 / 3,14 = r ( r + 40)
500 = r² + 40r
r² + 40r - 500 = 0
(r + 50)(r - 10)
r = - 50 cm      r = 10 cm

V = π r² t
V = 3,14 . 10² . 20
V = 3,14 . 100 . 20
V = 6280 cm³
Jawaban = C

Answer 2

dik : Luas tabung tanpa tutup = 1570 cm²
t = 20 cm
dit : V =...?

L = π . r (r + 2t)
1570 = 3,14 * r (r + 2 * 20)
1570 / 3,14 = r ( r + 40)
500 = r² + 40r
r² + 40r - 500 = 0
(r + 50)(r - 10)
r = - 50 cm      r = 10 cm

V = π r² t
V = 3,14 . 10² . 20
V = 3,14 . 100 . 20
V = 6280 cm³
Jawaban = C