Penjelasan dengan langkah-langkah:

3. A. 5/30 = y/(3y + 9)

1/6 = y/(3y + 9)

3y + 9 = 6y

9 = 6y - 3y

9 = 3y

y = 9/3

y = 3.

5/30 = x/(4x + 6)

1/6 = x/(4x + 6)

4x + 6 = 6x

6 = 6x - 4x

6 = 2x

x = 6/2

x = 3.

B. 6/36 = y/(4y + 4)

1/6 = y/(4y + 4)

4y + 4 = 6y

4 = 6y - 4y

4 = 2y

y = 4/2

y = 2.

6/36 = x/(3x + 5)

1/6 = x/(3x + 5)

3x + 5 = 6x

5 = 6x - 3x

5 = 3x

x = 5/3.

4. a.) BE.

6² + 8² = BE²

36 + 64 = BE²

100 = BE²

BE = 10.

AD.

6/18 = 8/(8 + x)

1/3 = 8/(8 + x)

8 + x = 24

x = 16.

CE.

6/18 = 10/(10 + x)

1/3 = 10/(10 + x)

10 + x = 30

x = 20.

CF.

Luas segitiga :

½ × a × t

½ × 24 × 18

12 × 18 = 216 cm²

AF.

Miringkan segitiga untuk mencari tinggi yang lain (AF)

216 = ½ × 30 × t

216 = 15 × t

t = 14,4. (AF)

18² - (14,4)² = 324 - 207,36 = 116,64

akar 116,64 = 10,8. (CF)

FB.

20 - 10,8 = 9,2.

b.) BE.

5² + 12² = 25 + 144 = 169 = akar 169 = 13.

AD.

5/25 = 12/(12 + x)

1/5 = 12/(12 + x)

12 + x = 60

x = 48.

CE.

5/25 = 13/(13 + x)

1/5 = 13/(13 + x)

13 + x = 65

x = 52.

CF.

½ × 25 × 60

30 × 25 = 750 cm²

AF.

750 = ½ × 65 × t

750 = 65t/2

1.500 = 65t

t = 23,07. (AF)

25² - (23,07)² = 625 - 532,2249 = 92,7751

akar 92,7751 = 9,98. (CF)

BF.

52 - 9,98 = 42,02.

5. A. Karton = 40 × 60

Foto :

panjang × (60 - 2 - 2)

panjang × 56

Ibaratkan panjang = x

x/40 = 56/60

x/40 = 14/15

15x = 560

x = 37,3 cm

40 - 37,3 = 2,7/2 = 1,35 cm.

B. Karton = 50 × 80

Foto :

(50 - 4 - 4) × lebar

42 × lebar

Ibaratkan lebar = y

y/80 = 42/50

y/80 = 21/25

25y = 1.680

y = 1.680/25

y = 67,2 cm

80 - 67,2 = 12,8/2 = 6,4 cm.

Semoga membantu.