Answer:
1.
The radius is given, so the radius is = 10
The radius is doubled to be a diameter, so (10 + 10) = 20 is your diameter
And to solve for circumference, your formula is;
C = 2πr
Where 'r' represents the radius, and 'π'(pi) is 22/7 or 3.14.
Plug in your values:-
C = 2πr
C = 2(3.14) x 10
C = 6.28 x 10
C = 62.8, so your circumference is 62.8.
2.
Your radius is half of your diameter, so,
D/2 = R
D = diameter
R = Radius
49/2 = 24.5 is your radius.
Your diameter is given, so the diameter is 49.
Use the formula we applied for circumference in our other problem;
C = 2πr
C = 2(3.14) x 24.5
C = 6.28 x 24.5
C = 153.86, so 153.86 is your circumference.