Below is the justification for the formula for area of a circle. Which word, when placed in the blank, best completes this argument?
The circumference of a circle is given by the formula C = 2pi r, where r is the radius.
If the circle is divided into equally sized sectors, the sectors can be
rearranged to form a shape that approximates a parallelogram.
The base of the parallelogram is _, and the height is r.
• Because the area of a parallelogram is equal to the product of the base
and the height, the area is pi r^2.
Therefore, the area of a circle is given by the formula pi r^2?.
A. The circumference, or 2 pi r^2 B. The radius, r C. Half of the radius or 1/2r. D. Half of the circumference, or pi r