Question

Help me with #9a, #9b, #9c, and #10. WILL GIVE BRAINLIEST

Answer 1

In general, if R is the radius of a circle, the area is
$Area = \pi R^2$

9a
The radius of the large circle is r, so
$Area = \pi r^2$

9b
The radius of the small circle is r/2, so
$Area = \pi (r/2)^2 = \pi r^2/4 = (1/4) \pi r^2$

9c
The area of a circle compared to another whose radius is twice as large is equal to 1/2^2=1/4 of the large circle.

As can be seen above, the factor is r^2 compared to (r/2)^2 which when expanded gives r^2 / 2^2 = r^2/4.

In general, the area of a figure varies with the square of the scale factor.