Tolong jawab pakai cara ya no 7 – 9

7.)
V.tabung kecil+V.tabung besar
= ((22/7 ×14×14) ×25) + ((22/7 ×21×21) ×20)
= 15.400 + 27.720
= 43.120 (c)

8)
6 × Luas sisi
= 6 × (18×18)
= 6 × 324
= 1.944 (b)

9)
2L.alas + L. selimut
= (2(22/7 ×7×7)) + (30×(22/7 ×14))
= 308 + 1320
= 1628 (a)

7)volume bangun 1
r=14 cm
t=25 cm
luas alas=π×r²
=22/7×14²
=22/7×196
=22×28
=616 cm²
v=La×t
=616×25
=15400 cm³
volume bangun 2
r=21 cm
t=45-25=20 cm
La=π×r²
=22/7×21²
=22/7×441
=22×63
=1386 cm²
v=La×t
=1386×20
=27720 cm³
volume seluruhnya=15400+27720=43120 cm³ (C)
8)6×s²
=6×18²
=6×324
=1944 cm²(b)
9)2×π×r(r+t)
=2×22/7×7(7+30)
=44(37)
=1628 cm²(a)