Penjelasan dengan langkah-langkah:

WHITEBOARD TEST

• R e m e d i a l

1. CD = CB

DE AB

15 = 10

5 x

x = 5 × 10

15

x = 5 × 2

3

x = 10

3

x = 3⅓ ✔

2. a = 70° → sehadap

b = 180° – 70° – 50°

b = 60°

3. a. < ABE = (2x + 10)° → sehadap

b. < BED = (2x + 10)° → bertolak belakang

• Segi 4 dan ∆

1. Persegi panjang

Keliling = 2 × (50 + 40)

Keliling = 2 × 90

Keliling = 180 cm

Luas = 50 × 40

Luas = 2.000 cm²

2. Jajar genjang

s = √(12²+5²) = √169 = 13 cm

Keliling = 2 × (50 + 13) = 126 cm

Luas = 50 × 12 = 600 cm²

3. Belah Ketupat

s = √[(10/2)²+(24/2)²]

s = √(25+144)

s = √169 = 13 cm

Keliling = 4 × 13 = 52 cm

Luas = ½ × 10 × 24 = 120 cm²

4. ∆ sama kaki ABC

AC = 2 × √(10²–8²) = 2 × √(100–64)

AC = 2 × √36 = 12 cm

Keliling = 12 + 2×10 = 32 cm

Luas = ½ × 8 × 12 = 48 cm²