The area of a circle varies directly as the square of the radius If the radius is tripled, by what factor will the area increase?

square-of-radius

#1

[ANSWER ASAP] The area of a circle varies directly as the square of the radius If the radius is tripled, by what factor will the area increase?

Answer:

Let’s figure this out by walking through an example.

[step1]Triple the radius of a circle
Original radius = 2 (I made this up)
New radius = 2 * 3 = 6 (we are supposed to triple the radius)

[step2] calculate the area of the two cirlces
Original area = πr2 = 4π
New area = 36π

[step3] compare the areas of the circles
So, our original area is 4π and the area of the circle whose radius we tripled is equal to 36π. 36/4 = 9, so we can say that the area increased by a factor of 9.