Jawaban:

12. V = πr^2 . t

= 3,14 . 10 . 10 . 20

= 314 . 20

= 6.280 cm^3

13. L = 6 × s^2

= 6 × 12 × 12

= 864 cm^2

14. V. balok = p × l × t

= 25 × 6 × 14

= 2.100 cm^3

L. balok = 2 (p × l + p × t + l × t)

= 2 (25 × 6 + 25 × 14 + 6 × 14)

= 2 (150 + 350 + 84)

= 2 (584)

= 1.168 cm^2

15. V. kubus = s^3

= 6 × 6 × 6

= 216 cm^3

V. balok = p × l × t

= 7 × 12 × 9

= 756 cm^3

V. gabungan = V. kubus + V. balok

= 216 + 756

= 972 cm^2

Uraian

1. K = π × d

= 3,14 × 30

= 94,2 cm

2. L = π . r^2

616 = 22/7 . r^2

r^2 = 616 ÷ 22/7

r = 196

r = √196

= 14 cm

3. V. prisma = luas alas × t

= 96 cm^2 × 14 cm

= 1.344 cm^3

4. Prisma segitiga mempunyai 5 buah sisi, yaitu 3 buah sisi disamping yang berbentuk persegi panjang, dan 2 sisi di alas dan atap yang berbentuk segitiga.

5. Dik : p = 20 dm = 200 cm

l = 50 cm

t = 70 cm

Dit : banyak air?

V. balok = p × l × t

= 200 × 50 × 70

= 700.000 cm^3 ÷ 1.000 = 700 liter

= 700 ÷ 1/2

= 350 liter

Penjelasan dengan langkah-langkah:

#semoga membantu, dan jangan lupa jadikan jawaban tercerdas ya:c)