How do you find the area of a circle using the radius of 3.14 when d is 30.5?
407637
The question is a little faulty but I think I know what you meant.\n\nIf d is 30.5, then r is half that, 15.25.  You mean pi which is about 3.14.\n\nIf I use that value of pi, and r is 15.25, then area is pi r squared, or 3.14 x 15.25 x 15.25 which is 730.24625.\n\nUsing a better value of pi, I got 730.61664.
667615
I'm sorry, miscalculated\nArea of a Circle= pi r^2\n3.14 x (5)^2\n3.14 x 25\nArea of the Circle is 78.5 meters
114473
If circumfrence = C (assume)\n   radius = r       (assume)\n   pi     = 3.14  or 22/7  (known value)\n\nthen :   C= 2 x (pi) x r \n          = 2 x  3.14 x 31/2\n          = 3.14 x 31   ( 2 gets cancelled out from the \n                          numerator and denominator)\n\n          = 97.34 units ( answer)
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
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.
593161
Simply use the corresponding equations. The circumference of a circle is Pi times the diameter and the area of a circle is Pi/4 times the diameter squared.\nThus doubling the diameter doubles the circumference, and quadruples the area.
910691
You need to work out the cross sections - which is bigger\n\ncross section is the area of the circle\n\n= pi times the radius squared\n\nwhat is bigger 2 pipes\n\n2 x 3.142 x 0.001^2\n\nor\n\n1 pipe\n\n3.142 x 0.002^2\n\nI get \n2 pipes = 6.284E-06\n1 pipes = 1.257E-05 therefore approx twice as much
1174230
I think you have to know how many degrees the segment is.  Then, calculate the area of the entire circle:\n\nPI x radius ^ 2 (squared)\n\nThen, divide the degrees in the segment by 360, so if your segment is 54 degrees, it's:\n\n54/360 = .15\n\nThen, multiply the result of the 2nd calculation (.15 in the example) by the area of the circle you calculated in step 1, and there's your answer.\n\nThere's probably a more elegant way, but it's been 25 years since I took a trigonometry or algebra course.
762697
The aswer to this question is really quite easy. \n\nSince we know that the shaded area is a square, finding its area is a simple matter.  Its area is s^2, or s squared, where s is the length of one edge of the square.\n\nTo find the area of the circle, we use the fact that for any circle, its area is  A = pi x r^2, or pi times r squared, where r is the radius of the circle.  To find a circle's radius, measure from the circle's center to any point on the circumference of the circle.  Multiply r by itself.  Then multiply that result by pi.  That gets you the area of the circle.\n\nWhat you seem to be looking for is the shaded area of the square remaining after removing the area of the circle.  To do this, simply subtract the area of the circle from the area of the square.\n\nYour formula should look something like this:\n\nA (shaded) =  A (square) - A (circle) \n                   =  s^2 - (pi x r^2)\n\nNotice that it does contain the constant pi.\n\nIf your circle is tangent to all sides of the square in which it is inscribed  (a single point on the circumference of the circle touches each side of the square at its mid-point), then your job is made easier still.\n\nA circle tangent to a circumsribed square (in this case a square constructed outside of the circle) has a radius equal to half the length of a side of the square.\n\nThen the above formula collapses to:\n\nA (shaded) = s^2 - (pi x (s/2)^2)\n                   = s^2 - (pi x (s^2/4))\n                   \nNote s^2/4 is read s squared divided by four.\n\nFactoring out common factors, we get \n\nA (shaded) =  s^2  x  (1)  -  s^2  (pi/4)             \n                   =  s^2  x  (1 - pi/4)\n\nNote that pi/4 is less than 1, so (1 - pi/4) is a positive number.\n\nHope this helps.
193691
area = r^2 * pi\narea = 9.8^2 * 3.1415\narea = 96.04 * 3.1415\narea is about 301.71
1175861
Area of Semicircle = (PI * R * R)/2\n\nAns. = 2.262 sq. cm
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
862969
pi*(radius)^2*height\n\npi is aprox. 3.14 or 22/7
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.
344528
The formula is as follows:\n\nC\n- = pi\nd\n\nC=the circumference\nd=the diameter\nand pi=3.14\n\nThe next step is to put all the known information into the equation:\n\nC\n- = 3.14\n14\n\nOnce you have that, you can multiply 14 by both sides to get C alone. Like this:\n\n14( C/14) = (3.14)14\n\n14 is canceled on the side with C, and the you take 3.14 and multiply it by 14 to get 43.96. So now the equation looks like this:\n\nC = 43.96\n\nAnd there you have your answer. The circumference of the circle with a diameter of 14 is 43.96\n\nHope this helped.
48612
Let r be the radius of the circle and s the length of the square's sides.\ncircle perimeter=2*pi*r, square perimeter=4*s\n2*pi*r=4*s => s=pi*r/2\ncircle area=pi*r^2, square area=s^2\ns^2=(pi*r/2)^2=pi^2*r^2/4\nBut pi<4 => pi^2*r^2/4<pi*r^2 => square area < circle area
1048814
If the circles are concentric, just subtract the area of the smaller circle from the larger circle:\n\nArea of small:  6*6*pi\nArea of large:  9*9*pi\n\nDifference of areas = 81*pi   -    36*pi  =  45*pi = 45 * 3.14159  = \n\n141.37 square units