# What is the area of circle whose radius is diagonal of a square whose area is 9?

2
by cuti33

2015-07-03T12:41:11+05:30

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Area of the square is 9,therefore side length of square is 3 units.
length of diagonal of suare is =sqrt{3^2+3^2} =3sqrt{2}
Area of circle=pi*[3sqrt{2}]^2
=18pi
=18*22/7
=56.57(approx.
)
2015-07-04T14:43:33+05:30
We know the formula for the area of a circle is  and for a square it is .

The "r" is the diagonal. Now let's find the side of the square. It is . Use trigonometry to find the diagonal.

We know two angles, namely the right angle and the 45.We know on side and considering the right angle is , the hypotenuse is the diagonal and the other side of the square is the opposite. Find the sine.

Therefore the diagonal is  . Now put in the area

The Area is 56.54 or .