Jawabanmu

2014-02-02T19:59:06+07:00
A) kllg = 785cm 

kllg = πD
785 = 3,14 D
785 : 3,14 = D
D = 250 cm

b) L= 1256cm²
L = πr²
1256 = 3,14 x r²
1256 : 3,14 = r²
400 = r²
r = √400
r = 20  ===> D= 2r = 2 x 20 = 40