When the radius of a circle is multiplied by a factor of 3, by what factor will the area of the circle change? the area of a circle with radius 3 as big as the area of a circle with radius 1.

Yes, the circle's area will change because the radius is different and when you go to do the formula for area the radius will not be the same it will have tripled. The area of the circle with a radius of 3 would be 28.26. The area of the circle with a radius of 1 would be 3.14. The area of a circle with radius 3 is 9 times as big as the area of a circle with radius one. So the answer is 9. Hope that helped.