Jawaban harus tulis di buku
14). Sisi lengkung besar (½ lingkaran):
d = 14 cm
K = ½ × π × d = ½ × 22/7 × 14
= ½ × 22 × 2 = 22 cm
Sisi lengkung kecil ((2) ½ lingkaran = 1 lingkaran):
d = 14/2 = 7 cm
K = π × d = 22/7 × 7 = 22 cm
Total: 22 + 22 = 44 cm
15). Luas seluruhnya (½ lingkaran):
d = 14 cm, r = 14/2 = 7 cm
L = ½ × π × r² = ½ × 22/7 × 7 × 7
= ½ × 22 × 7 = 11 × 7 = 77 cm²
Luas tidak diarsir ((2) ½ lingkaran = 1 lingkaran):
r = 14/4 = 7/2 cm
L = π × r² = 22/7 × 7/2 × 7/2
= 22 × ½ × 7/2 = 11 × 7/2
= 77/2 = 38,5 cm
Luas diarsir: 77 – 38,5 = 38,5 cm²