THE CORRECT ANSWER IS (C). THE AREA OF A CIRCLE ISPR2. THE AREA OF...
21. The correct answer is (C). The area of a circle is
pr
2
. The area of a circle with a radius
of x is
px
2
, which is given as 4. The area of a circle with radius 3x is
p(3x)
2
5
9px
2
.
Therefore, the area of the larger circle is 9 times the area of the smaller circle, or 36.