tlg bntu bsk d kmpln

4. K = 3,14 × d = 3,14 × (20 × 2) = 3,14 × 40 = 125,6 cm
L = 3,14 × r × r = 3,14 × 20 × 20 = 1256 cm2

5. K = 3,14 × d = 3,14 × (40 × 2) = 3,14 × 80 = 251,2 cm
L = 3,14 × r × r = 3,14 × 40 × 40 = 5024 cm2

6. K = 3,14 × d = 3,14 × 70 = 219,8 cm
L = 3,14 × r × r = 3,14 × (70 ÷ 2 ) × ( 70 ÷ 2 ) = 3,14 × 35 × 35 = 3846,5 cm2

7. K = 3,14 × d = 3,14 × 84 = 263,76 cm
L = 3,14 × r × r = 3,14 × ( 84 ÷ 2 ) × ( 84 ÷ 2 ) = 3,14 × 42 × 42 = 5538,96 cm2

8. K = 3,14 × d = 3,14 × 100 = 314 cm
L = 3,14 × r × r = 3,14 × ( 100 ÷ 2 ) × ( 100 ÷ 2 ) = 3,14 × 50 × 50 = 7850 cm2

semoga membantu

4. r = 20 cm, D = 40
    K = π x D
       = 3,14 x 40 = 125,6 cm
    L = π r²
       = 3,14 x 20 x 20 = 1256 cm²

5. r = 40, D = 80
    K = π x D
       = 3,14 x 80 = 251,2 cm
    L = πr²
       = 3,14 x 40 x 40 = 5024 cm²

6. D = 70, r = 35
    K = π x D
       = 22/7 x 70 = 220 cm
    L = πr²
       = 22/7 x 35 x 35 = 3850 cm²

7. D = 84, r = 42
    K = π x D
       = 22/7 x 84 = 264 cm
    L = πr²
       = 22/7 x 42 x 42 = 5544 cm²

8. D = 100, r = 50
    K = π x D
       = 3,14 x 100 = 314 cm
    L = πr²
       = 3,14 x 50 x 50 = 7850 cm²