Given: D = 8 1/2 in.
We know that the diameter of a circle is twice the radius. Therefore, we can find the radius by dividing the diameter by 2:
radius (r) = D/2 = 8 1/2 / 2 = 4 1/4 in.
To find the circumference (C) of the circle, we can use the formula:
C = 2πr
where π (pi) is a constant approximately equal to 3.14.
Substituting the value of r, we get:
C = 2π(4 1/4) = 2π(17/4) = 8.5π
Therefore, the radius is 4 1/4 in. and the circumference is 8.5π in.