Question

No 28, 29, 30 plis jawab

Answer 1

28. ubah 1,2m ke 120 cm, 154 liter  ke 154000 cm³ 
Volume total = volume cuci + volume sisa 
tinggi total (t0) = tinggi cuci (t1) + tinggi sisa (t2)

πr² t0 = πr² t1 + πr²t2
πr²t0 = 154.000 + πr²t2
154.000= πr²t0 - πr²t2
154.000 = πr² (t0 - t2)
154.000/ πr² = t0 - t2
154.000/ π 35² = t0 - t2
40 = t0 - t2
40 = 120 - t2
t2 =120 - 40 = 80 (b)

29. d= 20 ---> r = 10 
L = 2πrt --> L/ 2t =πr

V tabung = πr²t = πr rt
V tabung = (L/2t) rt
V tabung = (L/2) r
V tabung = (314/2) 10
V tabung = 157 . 10
V  tabung = 1570 (a)

30. panjang alas kerucut = 120/360 2πr = 1/3 2π42
panjang alas kerucut = 88

cari jari-jari alas kerucut
88= 2πr
88= 2 . 22/7 . r
88 = 44/7 . r
88/ 44 = r/7
2 = r/7
r= 14 cm --> d = 28 cm (c)