Below is the justification for the formula for area of a circle. Which word, when placed in both blanks, best completes this argument?
• The circumference of a circle is given by the formula C - 287 where ris 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 half the circumference, or *, and the
height of the parallelogram is n
of the base
• Because the area of a parallelogram is equal to the
and the height, the area is the of Tr andr, or 1/2
• Therefore, the area of a circle is given by the formula r2

a. sum sum
b. quotient quotient
c. product product
d. difference, difference