Question

The radius of a circle is multiplied by 7. Its area is _____ times bigger than the original circle.

Answer 1

Do you know the formula for the area of a circle?

Answer 2

area = pi times r^2

Answer 3

Good!
Say that the radius of the original circle is r. The new circle, accordingly, is 7r. Try plugging in 7r into r for the area of the new circle

Answer 4

49?

Answer 5

No, actually just like this: A= pi times (7r)^2 which equals A = pi times 49 times r^2

Answer 6

If you set this new equation to the old one, you can see just how much bigger the second circle is.

Wait, were you asking if 49 was the answer? Sorry if I misunderstood. Yeah that's right

Answer 7

Yeah I was saying 49 is the answer. Sorry about the confusion.