If the radius of a circle is r cm

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If the radius of a circle is r cm, what is the area of the circle? If the radius is increased to 2r cm, what is the area of the circle?

Rose98 Sep 15, 2014

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Best Answer

Rose, you can get the formula for the area of a circle on the from the formulary page on this site. It is

$A=\pi r^2 \quad cm^2$

Now if the radius is doubled it becomes 2r the new area will be

$\\A=\pi\times (2r)^2\\ A=\pi \times 2^2 \times r^2\\ A=4\pi r^2\quad cm^2\\$

Melody Sep 15, 2014

Melody · Answer 1 · 2014-09-15T10:24:54

Rose, you can get the formula for the area of a circle on the from the formulary page on this site. It is

$A=\pi r^2 \quad cm^2$

Now if the radius is doubled it becomes 2r the new area will be

$\\A=\pi\times (2r)^2\\ A=\pi \times 2^2 \times r^2\\ A=4\pi r^2\quad cm^2\\$

rosala · Answer 2 · 2014-09-15T07:40:28

Rose do you know whats the formula to find the area of the circle , if so can u tell me?