how to get the square foot of a circle?
915242
The area of a circle is calculated by multiplying pi (3.1415926) by the radius squared.  If you want it in square feet, make sure that you measure the radius in feet as well.
50370
Draw a circle.  From the centre point to the edge draw a straight line.  This is the radius.  The area of a circle is pi times (radius squared.)  The Perimetre of a circle is 2 times pi times radius.
375776
In a square: multiply lenght by wittd.\n\nIt all revolves around that\n\nTriangle: base * height /2\n\nCircle: pi ( the matematical value - 3.1416 ) * radius^2\n\nThose are the basic formulae
229888
So 2*pi*radius = circumference.  And you know the circumference, so set up a little equation and solve for the radius.\n2 pi R = 4 pi\ncancel the 2 and the pi to get\nR = 2\nNow you can easily find the area using Area = pi * R^2
1043560
easy if its circular: square the diameter (multiply the diameter by itself) then multiply the diameter  by 3.142, divide the answer by 4, then multiply this answer by the height of the pool.
701955
You could use graph paper to get a good approximation of the surface area. Using a large circle would increase the accuracy.\nCount the whole squares, then count the half squares. \n\nAlternatively would be to use graph paper, then precisely cut out the circle, then cut the graph paper. On another sheet of graph paper, try to fill squares with the incomplete pieces from the circle.\n\nModifying Mike's answer, using a sensitive microbalance, find an average mass of one graph square then measure the mass of the cut out circle.
976475
height by width measured in feet
204855
Looks to me like you are trying to figure out a "PERIMETER" rather than an "AREA".  If so, you need to ADD the lengths of all the sides together.  If you ARE looking for an area, it is simply Length x Width (for a rectangle or square), 1/2 the base x height (for a triangle), or Pi x radius squared (Pi is approximately =3.1415926) for a circle.  If the "shape" of the object you are trying to find the area of is irregular, then you must divide it up into these familiar shapes first, find EACH individual area, then add those areas together for the total area.
743021
1225π ft^2\nPicture:\nhttp://mudandmuck.com/str2/cup2.revised.gif\nr = radius of small circle\nR = radius of Carousel\n\n35^2 + r^2 = R^2\n1225 = R^2 - r^2\narea of floor to paint = (Area of carousel - area of small circle (machinery in the way)) = πR^2 - πr^2 = π(R^2 - r^2) = 1225π
188331
Area = pi times r squared\n\nDivide 199 by pi, this will be r^2\n\nDo the square root of this to get r\n\nThen double it to get d\n\nIf you use the pi button for pi, it is 15.917747 ft
378913
Do you mean like an object that has a semi-circle on one end?\n\nIf yes, you can find the area of the semi-circle by figuring the area of the entire circle and dividing by half. Then you just find the area of the rectangular portion and add the two answers.
1150077
Any length greater or equal the circumference of a 1-acre circle. \n\nCalculate the acre as square feet, square yards or square meters.\n\nDivide by pi and calculate the square root to get the radius, then multiply by 2 pi for the circle circumference.
442228
the side of a decagon is exactly (sqrt(5)-1)/2 times the radius of the external circe.\nIf your circle has a diameter of 6 foot (that is, your 6 foot lenght is the distance between two opposite vertexes), then calculate (sqrt(5)-1)*3/2 and you get the side of the decagon in feet.\n\nIf your value of 6 foot is the distance between two opposite sides (from the middle point of a side to the middle point of another side), then you have a apotheme of 3 feet. \n\nNow, the radius is 2/(sqrt(5)-1) times the side of the decagon = 1/(sqrt(5)-1) the half-side of the decagon.\n\nApplying the Pythagorean theorem you have that the square of the apotheme is worth ((1/(sqrt5 - 1))^2 - 1^2) times the half-side, that is \n\n9 ft = ((1/(sqrt5 - 1))^2 - 1^2)*(X/2)    (X = lenght of the side)\n\nthat is \n\n(X/2) = (9-(1-(5+1-2sqrt5))/(5+1-2sqrt5))\n\nthat is \n\n(X/2) = (9 - (2sqrt5 - 5)/(6-2sqrt5))\n\nX = 2*(54 - 18sqrt5 - 2sqrt5 + 5)/(6-2sqrt5)\n\nTHAT IS:\nX = (59 - 20sqrt5)/(3-sqrt5)  feet
255850
I assume the shape to be rectangle.\n\nMeasure the longer side in feets and name it L\nand the shorter side as B\n\nThen multiply L*B you get measure in square feets.\n\nIf it is irregular in shape, you have to cut it into parts and draw lines and measure each area separately.
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.
981115
that way you can remember the formula with generic terms like L and W then later insert the corresponding numbers.\n\nlength times width equals area\nL * W = A\nl2" * 12" = 144 square inches
634060
The length of one side of the rectangle can be related to the Circumference of the circle.\nTo get the perimeter of a circle, called the circumference of the circle, one simply has to multiply 2 times pi (about 3.14) times the radius of the particular circle. \nThe circumference of a circle can be calculated from its diameter using the formula:\nc = πd\nOr, substituting the radius for the diameter:\nc = 2πr\nWhere r is the radius and d is the diameter of the circle, and π (the Greek letter pi) is the constant 3.141 592 653 589 793...