Jawaban:

1. ∠ABC + ∠BCD + ∠CDA + ∠DAB = 360°

∠ABC = ∠CDA = 118°

∠BCD = ∠DAB = x

118° + x + 118° + x = 360°

236° + 2x = 360°

2x = 124°

x = 62°

Maka, ∠BCD = 62°

∠BCA = 1/2 × ∠BCD = 1/2 × 62° = 31°

2. Keliling persegi panjang = 2 × panjang + 2 × lebar

= 2 × 16 cm + 2 × 10 cm

= 32 cm + 20 cm

= 52 cm

3. Luas Layang - Layang = 1/2 × Diagonal 1 × Diagonal 2

= 1/2 × 18 cm × 20 cm

= 9 cm × 20 cm

= 180 cm²

4. Luas Daerah yang diarsir = Luas Persegi Besar - Luas Persegi Kecil

Luas Persegi Besar = 10 cm × 10 cm = 100 cm²

Luas Persegi Kecil = (10 - 6) cm × (10 - 6) cm = 4 cm × 4 cm

= 16 cm²

Luas Daerah yang diarsir = 100 cm² - 16 cm² = 84 cm²

5. Luas Segitiga = 1/2 × Alas × Tinggi

= 1/2 × 13 cm × 12 cm

= 6 cm × 13 cm

= 78 cm²