Jawaban:

L = 4 x \piπ x r^2

729\piπ = 4\piπ x r^2

r^2 = 729\piπ : 4\piπ = 182,25

r = \sqrt{182,25}

182,25

= 13,5 cm

b. V = 4/3 x \piπ x r^3

2304\piπ = 4/3\piπ x r^3

r^3 = 2304\piπ x 3/4\piπ = 1728

r = \sqrt[3]{1728}

3

1728

= 12 cm

c. 36\piπ = 4/3\piπ x r^3

r^3 = 36\piπ x 3/4\piπ = 27

r = \sqrt[3]{27}

3

27

= 3 cm

d. L = 1/2 x 4 x \piπ x r^2

L = 2 x \piπ x r^2

27\piπ = 2\piπ x r^2

r^2 = 27\piπ : 2\piπ = 13,5

r = \sqrt{13,5}

13,5

= 3,67 cm

e. r^2 = 45\piπ : 2\piπ = 22,5

r = \sqrt{22,5}

22,5

= 4,74 cm

f. r^3 = 128/3\piπ x 3/4\piπ = 32

r = \sqrt[3]{32}

3

32

= 3,1 cm