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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.
Is 2Pi r the same as Pi r squared?
No. 2Pi r is equal to Pi d, though.
What is the formula using pi for the area of a circle?
area of a circle is equal to pi times the square of its radius.. A=(pi)r^2
Surface area of a cylinder?
A cylinder of radius R and length L has a surface area equal to: Area = Area of 2 Circular Faces + Area of Tube = 2 * Pi * R2 + 2 * Pi * R * L Area = 2 * Pi * R * (R+L) where Pi = 3.14 (rounded) Another way to look at it is: 2 * Pi * R2 + Pi * d * h. H= height R= radius D= diameter 2= squared
What is pi r r?
Pi times r times r or Pi r squared is the formula for finding the area of a circle where r is the radius
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.
Is 2Pi r the same as Pi r squared?
No. 2Pi r is equal to Pi d, though.
Why is circumference equal to 2 times Pi times r?
Circumference = pi times diameter or Circumference= two x pi x radius. Now remember the diameter of a circle is the straight line from one edge of the circle, through the centre to the opposite edge. The straight line from the edge to the centre is the radius, and then from the centre to the opposite edge is another radius. So the diameter is the length of two radii. Algebraically express as d = 2r. So Algebraically C = pi*d Substituting the 'd' for '2r' C = pi2r However in algebra coefficient numbers are expressed to the left. Hence C = 2pir Why 'C' is this expression I would have to go into some 'very heavy' differential calculus. Suffice it to say, the ancients found that the circumference traced by a donkey/mule driving water out of well was directly proportional to the diameter, twice the length of the tether(2 radii). From this they discovered that for however long the the tether and the circumference were. they had a constant of proportion C directly related to diameter. This is equated to C = kd And k = C/d , which was founf to be 3.141592..... which now call 'pi'. for any sized circle. So today in school you learn C = pi d or C = 2 pi r And for circular area(A) A = pi r^(2) The 'pi' youare given in school is proabably 3.14 , 3.1416 or 22/7 . However, these values are Approximatons, because 'pi' is an irrational number. Hope that helps!!!!!!
How do you find the radius of a semi circle with an equal perimeter to a rectangle with 1 side 3cm and the other side equal to the radius?
Suppose the radius is R cm. Then the perimeter of the rectangle is 2*(3+R) = 6 + 2R cm. The length of the arc of the semicircle is pi*R and the length of the diameter is 2*R so the perimeter of the semicircle is pi*R + 2R The two perimeters are equal so 6 + 2r = pi*R + 2R That is, 6 = pi*R and so R = 6/pi
Q149 The perimeter of a circle and square are equal The ratio of their area is?
Equal perimeters:2 pi R = 4 spi R = 2 ss = pi R / 2Ratio of areas:pi R2 / s2 = (4 pi R2) / (pi2 R2) = 4 / pi= 1.2732 (rounded)The area of the circle is [ (4/pi) x (area of the square) ].
What the answer to the area of a circle?
The area of a circle = Pi*r2 where r is the radius and Pi is approximately equal to 3.14
What is the area of a circle that has a radius equal to 1?
a=pi times r squared so pi or 3.1415926535898...
What is the formula using pi for the area of a circle?
area of a circle is equal to pi times the square of its radius.. A=(pi)r^2
A sphere with a diameter of 16 meters has the same surface area as the total surface area of a right cylinder with the base diameter equal to the sphere diameter how high is the cylinder?
Surface Area of Sphere = 4*Pi*r2 Surface Area of Cylinder = 2*Pi*r2+2*Pi*r*h If we set them as equal: 4*Pi*r2 = 2*Pi*r2+2*Pi*r*h ' Factor out 2*Pi*r 4*Pi*r2 = 2*Pi*r*(r+h) ' Divide both sides by 2*Pi*r 2*r=r+h ' Subtract r from both sides r=h Diameter = 2*r so h=d/2 In this case, d=16m h=8m
What is the volume of cone?
The volume of a cone is equal to 1/3*(pi)*r^2*h. r=radius pi=3.14 h=height
How do you find the circumference of a circle with just the radius?
The circumference of a circle is equal to the radius times 2*pi. 2*pi*R where R is the radius.
How do you find the radios from the area?
The are of a circle can be expressed by: A = (pi) r^2 So in order to find the radius from the are, you just have to solve this equation for "r". A/(pi) = r^2 (A/(pi))^(1/2) = r Or in words: The radius is equal to the square root of the quantity: area divided by pi.
