Page 148 - Buku Paket Kelas 8 Matematika Semester 2

No.
Prisma
Luas permukaan prisma
2.
6 cm 6 cm
6 cm 6 cm
8 cm
I
8 cm
8 cm
I
8 cm
6 cm 6 cm
6 cm 6 cm
8 cm
8 cm
II
III
IV
V
Luas = 2 × I + II + III + IV + V = 2 × (8 × 6) + (6 × 40)
+ (8 × 40) + (6 × 40) +
(8 × 40)
= 2 × (8 × 6) + (6 + 8 + 6 + 8) × 40
= 2 × (8 × 6) + 2 × (8 + 6) × 40
= 2 × (48) + 2 × (14) × 40 = 96 + 28 × 40
= 96 + 1.120
= 1.216
Jadi, luasnya adalah 1.216 cm2.
3.
10 cm 10 cm I
10 cm 10 cm
10 cm 10 cm
10 cm
10 cm
10 cm
10 cm 10 cm
II
III
IV
V
VI
VII
10 cm 10 cm
10 cm
10 cm
I 10 cm
t
10 cm
Luas = 2 × I + II + III + IV + V + VI + VII
= 2 × I + II + II + II + II + II + II
= 2 × I + 6 × II =2×(6×12×10×5 3)
+ 6 × (10 × 30) =2×(150 3)+6×(300) = 300 3 + 1.800
Jadi, luasnya adalah (300 3 + 1.800) cm2.
Keterangan:
t = 102 −52
100−25 = 75
=
=5 3
140
Kelas VIII SMP/MTs Semester II
40 cm
40 cm
30 cm
30 cm
10 cm
10 cm
10 cm
10 cm