Tolong di jawab nomor 12 sampai 15

Tolong di jawab nomor 12 sampai 15

12)
Lp = 2 × La + Ka × t
$= 2 times ( frac{9 times 12}{2} ) + (9 + 12 + 15) times 40 \ = 108 + 1440 \ = 1548$

13) luas permukaan balok
$= 2 times (p times l + p times t + l times t) \ = 2 times (24 times 18 + 24 times 12 + 18 times 12) \ = 2 times (432 + 288 + 216) \ = 2 times 936 \ = 1872$

14) luas permukaan limas
$= 4 times frac{5 times 12}{2} \ = 4 times 30 \ = 120$

15) volume
$= (80 times 80 times 20) + (80 times 80 times 90) + (80 times 80 times 50) \ = 128000 + 576000 + 320000 \ = 1024000$