Monday, June 22, 2015

Calculate the area of the circle if we are given that equation of the circle as x^2 +y^2 - 8x +12y = 12

Given the equation of the
circle:


x^2 + y^2 - 8x + 12y =
12


We need to rewrite the equation into the standard form
in order to determine the radius.


==> (x-a)^2 +
(y-b)^2 = r^2


Then we will need to complete the
square.


==> x^2 - 8x + 16 -16 + y^2 + 12y + 36 -36 =
12


==> (x-4)^2 + (y+6)^2 = 12 + 36 +
16


==. (x-4)^2 + 9y+6)^2 =
64


==> (x-4)^2 + (y+6)^2 =
8^2


Then the radius is r=
8.


Now we will calculate the
area.


==> A= r^2 * pi = 8^2 * pi = 64*pi =
201.06


Then the area of the circle is 64pi =
201.06 square units.

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