What is the formula for finding the area of a circle?
447001
pie times radius squared
598391
First find the area of the circle that is on the top or bottom of the cylinder. The area formula for a circle is \n\n"pi,r squared. That means multiply pi times the radius of the circle which you have to square first.\nThen you take the number that you get and multiply it by the height of the cylinder.\nGood luck.
174683
The simple way to find the area of any shape is to break it up in to trangles and squares.  \n\n\nOr use integration... but i do not think that is what you are looking for
589996
Assuming that A, B, C are all on the same line.\n\nLarger circle:\nRadius = AC = 6\nArea = PI * r^2 = 36*PI\n\nSmaller circle:\nRadius = AC - AB = 6 - 2 = 4\nArea = PI * r^2 = 16*PI\n\nShaded area:\nArea = (Large A) - (Small A)\n     =  36*PI - 16*PI = 20*PI = 62.8 units^2
650879
Use string, paper, and a ruler.  The string can represent the perimeter, and you can draw a grid on the circle to represent the units of area.  Just don't get too in depth on the origins of pi.
784010
Take the formula for the surface area(S) and solve for r\nS=4*pi*r^2\nr^2 = S/(4pi)\nr =squareroot(S/4pi) or (S/4pi)^(1/2)\n\nNow take the formula for the volume\n4/3*pi*r^3\nand substitute the formula for r into the equation\n4/3*pi*(squareroot(S/4pi))^3\n4/3*pi(S/4pi)^(3/2)
472218
I'm assuming that A and B are on the circle and O is the center of the circle.  Since OB=6, AB=6 as well, since OB and AB are radii.\n\n1.  Area of a circle = pi*r^2\n= pi*(6)^2\n= 36pi\n\n2.  Area of a sector (pie wedge) is easiest if you consider that the pie wedge is a certain fraction of the whole circle.  In this case, your sector is 60 degrees, and the whole circle is 360 degrees.  So the sector is 1/6 of the total area, which we found in part 1.  So the area = 6pi.\n\n3.  The segment is trickier.  If you look at the triangle, the segment is the curved part - almost like the top of the ice cream cone, if you can follow my description.\n\nThe area of a segment is given by\n\nA = r^2[theta - sin(theta)]/2\n\nwhere theta is the angle in radians.  The angle we have is 60 degrees.  To convert to radians, multiply by pi/180.  So theta is pi/3.\n\nNow since we know that the triangle has a 60 degree angle, and that OA and OB are both 6, through some reasoning we can see that this is an equilateral triangle, and AB (the chord) is also 6.\n\nSo the area of the segment then is\n\nA = r^2[theta - sin(theta)]/2\n= (6)^2[pi/3 - sin(pi/3)]/2\n= 3.26\n\n4.  Circumference = 2*pi*r\n= 2*pi*6\n= 12pi\n\nI don't think that X served any purpose except to indicate the region you're supposed to be considering for this problem.
40239
A= pi x Radius(squared)\nA= 3.14 x 10 (squared)\nA= 3.14 x 100\nA= 314\n\n*2piR is the formula to find the CIRCUMFERENCE of a circle. (the second answer is wrong.)
369376
Area of a circle = pi * r^2\n= pi * 118^2  <--take half of 236 mm to find the radius\n= 43744 mm^2\n\nArea of a square = s^2\n43744 = s^2\ns = 209 mm\n\nSo your square has to have sides of 209 mm if it will have the same area as the circle above.
303304
Use the well known formulas that relate the radius and diameter of a circle to its circumfrence.\n\nC = pi * D\nC = 2 * pi * R\n\nFor pi, you can use 3.14 or 22/7, or whatever value your teacher wants you to use.
243669
divde the area by pi, then take the square root.  Multiply that reult by 2 and then by pi and your done.
239617
A circle consists of all the points on a plane equidistant to a single point (the center.)\n\nIt's mathematical formula is:\n\ny = sqrt(r^2 - x^2) \nwhere r = radius and the center is at origin.
471852
Area of a circle = pi*r^2 and the radius is half of the diameter, so 15 feet in this case. (15 feet)*(15 feet)*3.14 = 706.5 feet^2\n\nSo about 706.5 square feet.
426495
It depends on what shape you want to know the area.\n\nSimple shapes have formulas. (such as a circle's area is Pi*r*r)\n\nComplex shapes which have pattern.(you know the equation of lines that form the shape), calculus is used to find the area.\n\nIf a shape is not ordinary. You should draw lines to grid it and count the area square by square.\n\n-Hope this would help-
234883
The symbol p is called pi and is approximately equal to 22/7 or 3.141592654 , most high school teachers use it to two decimal places as 3.14\np is the ratio between the circumference and the diameter of a circle ..i.e \np = (circumference / diameter ).\nInterestingly the value of p is the same for any circle ... \n\nArea of circle = p x ( radius x radius ) = p radius2\n\nif the Radius = R \nthen \nArea of circle = pR2 = p x R x R \n\nHere's an example:\nFind the area of the circle with radius 10 cm ..use p as 3.14\nAnswer\nHere we have :\nRadius = 10 cm\np = 3.14\n\nUsing the formula Area of circle = p radius2 = p x radius x radius \n\nreplacing radius with 10 cm and p with 3.14 in above formula we have\n\nArea of circle = p radius2 = p x radius x radius = 3.14 x 10cm x 10cm = 3.14 x 100 cm2 = 314 cm2
608708
The basic formula for a circle is (x-h)^2 + (y-k)^2 = r^2\n\n(h,k) would be the center (where x=h and where y=k), and the radius is the positive square root of r^2\n\nSo in your example, there is no h or k, so the center would be (0,0) and the radius would be the positive square root of 25, which is 5.
568696
rare gem's answer is right..given the radius you'll just need to compute for the area using the formula right?\n\nArea=(radius^2)(pi)\n    = (5)(5)(pi)