Question

Jika luas tabung 16.500 dan tinggi tabung 40 cm. tentukan luas tutup tabung?

Answer 1

Ltabung = 2πr(r+t)
16500 = 2.22/7.r(r+40)
16500 = 44/7 (r²+40r)
16500.7/44 = r²+40r
2625 = r²+40r
r²+40r=2625
(r+20)²-400=2625
(r+20)²=3025
r+20 = 55
r = 35 cm
L tutup = πr²
           = 22/7 . 35. 35
           = 3850 cm²