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What is the diameter of a 160 feet circle?
If circumference = 160', and circumference = 2 x pi x r, then... 160 = 2 x pi x r 80 = pi x r 80/pi = r 2(80/pi) = diameter = 50.99'
What is the area of a circle that is 120 ft in circumference?
Circumference of circle = 2 x pi x r where r is the radius. So we have here 120 = 2 x pi x r or 60 = pi x r or 60 = 3.1415 x r, Hence r = 60/3.1415 = 19.099 Area of circle is pi x r x r, here it is 3.1415 x 19.099 x 19.099 = 1145.93 square feet
What is the formula for finding the circumference of a semicircle?
2 pi r = circumference. 1/2 of that is pi x r. pi is 3.142
What is the formula using pi for the circumference and area of a circle?
Circumference: C = 2 x pi x r Area: A = pi x r2 Where: pi = about 3.1416, r is the radius (half the diameter).
The formula for the circumference of a circle is what?
Circumference of a circle = diameter*pi or 2*pi*radius
What is the diameter of a 160 feet circle?
If circumference = 160', and circumference = 2 x pi x r, then... 160 = 2 x pi x r 80 = pi x r 80/pi = r 2(80/pi) = diameter = 50.99'
How do you find the are of a cylinder?
surface area=2 x pi x r² + 2 x pi x r x h volume = pi x r² x h
What does 2 pi r or 2 pi radius mean?
2 x Pi x r is equal to the circumference of a circle whose radius is equal to r.
What is the surface area of a circle with a circumference of 28?
Circumference of a circle: 2 x Pi x r (with r = the radius of the circle).Area of a circle: Pi x r x rThe circumference is 28, so:2 x Pi x r = 28r = 28 / (2 x Pi)Area = Pi x (28 / (2 x Pi)) x (28 / (2 x Pi)) = 62.4[rounded on one decimal] or more accurately (196 / Pi).
How do you find the radius of a circle if all you know is the circumference?
C = circumference r = radius C = 2 x pi x r C / 2 = pi x r C / 2 / pi = r
What happens to circumferences and areas when the radius of circle is multiplied by some number x?
The circumference of a circle is 2 * pi * r. If you multiple r by x you get 2 * pi * (r * x) which is the same as x * (2 * pi * r). So the circumference is multiplied by x. The area of a circle is pi * r2. Multiply r by x and you get pi * (rx)2 which is the same is (pi * r2) * x2. So the area gets multiplied by x2.
How do you find the radius of a sphere that has a ratio of 1 to 2 for volume and surface area?
Surface area of sphere is 4 x pi x r x r Volume of sphere is (4/3) x pi x r x r x r Hence ((4/3) x pi x r x r x r) / (4 x pi x r x r) = 1/2 ((4/3) x r) / (4) = 1/2 (1/3) x r = 1/2 r = 1 and 1/2
How do you find the surface area of a cylinder in terms of pi?
2 x pi x r = A so pi=A/r times2
What is a formula for calculating the radius of a circle when the circumference is known?
The way to find the circumference is either 2 x pi x r, or pi x d.So rearrange the formula:circumference = 2 x pi x rcircumference / 2 x pi = rSo take the circumference, and divide it by 2 pi and you have the radius.A:Using the formula for circumference which is 2(pi)r solve for r. Now you have radius = circumference/(2pi). The formula for area of a circle is (pi)r^2. Substituting r with circumference/(2pi) you get area = pi(circumference/(2pi))^2. When you simplify you get area = circumference^2/(4pi).
What if the formula for surface area of a cylinder?
The surface area of the vertical part of the cylinder is 2 x pi x r x h where r is the radius of the cylinder and h is the height. Now you have calculate the area of the two end circular areas. Each of them is pi x r x r, so two of them is 2 x pi x r x r Total surface area = (2 x pi x r)(h + r)
Why can C Pi x d or C 2 x Pi x r be used to find circumference?
Because [ d = 2 r ].
How do you figure the radius if you have the circumference?
The circumference C of a circle can be written as C = 2 x pi x r, where r is the radius. Thus, to get C, you divide both sides of the equation with 2 x pi and get r = C/(2 x pi).
