panjang, lebar, dan tinggi sebuah balok berturut-turut a cm, b cm, c cm. keliling alas balok 76 cm, keliling sisi tegak depan 80 cm, dan keliling sisi samping k

jawab
p= a
l = b
t = c

kelilin alas =  76
2(p+l) = 76
p + l = 38
a + b  = 38 ...(i)

keliling sisi tegak depan = 80
2(p+t) = 80
p + t = 40
a + c = 40 ...(ii)

keliling samping kanan = 68
2(l+t) = 68
l + t = 34
b + c = 34....(iii)

(i) dan  (ii)
a + b = 38
a+ c = 40 ...(-)
b - c = - 2 ...(iv)

(iii) dan (iv)
b + c = 34
b - c = - 2....(+)
2b = 32
b  = 16

b + c = 34
c = 34 - b =  34 - 16
c = 18

a+ b = 38
a + 16 = 38
a = 22

p = a = 22
l = b = 16
t = c = 18

Volume = p . l . t = 12 x 16 x 18
V = 3.456 cm³