the area of a circle is represented by the following equation; A=pi*R2 where A is area, pi is the number pi (3.1415926.......for most high school maths, 3.14 is suitable) and R is the radius. So, square your radius, and multiply it by pi.
Its just the area of a circle 21 inches or 21 centimeters? area of a circle is (pi)*r2 where pi = 3.1415.... and r = radius thus A = (3.1415)*(diameter/2)2 u can figure out the answer from that with a calculator
If radius=21 ft, then diameter = 2*radius = 42 ft
the radius is 10.5 inches. * * * * * Wrong! Circumference = 2*pi*Radius Or, Radius = Circumference/(2*pi) So circumference = 21 inches implies radius = 3.34 inches (to 3 sf)
Well, honey, a 42-inch diameter circle has a radius of 21 inches. To find the area, you gotta use the formula A = πr^2. So, plug in 21 for the radius, square it, multiply by π, and you get approximately 1385.44 square inches. And if you wanna convert that to square feet, just divide by 144 because there are 144 square inches in a square foot. So, the answer is about 9.63 square feet.
Well, darling, the circumference of a circle is calculated using the formula C = 2πr. So, with a radius of 21 cm, you just plug that bad boy in and get C = 2 x π x 21 = 132 cm. Voilà, there you have it!
About 1385.44cm2
The area of a circle of radius 21 is 1386
The area of a circle is calculated using the formula A = πr^2, where A is the area, π is a constant approximately equal to 3.14159, and r is the radius of the circle. Plugging in the radius of 21cm into the formula, we get A = 3.14159 x (21)^2 = 1385.44 square centimeters. Therefore, the area of a circle with a radius of 21cm is 1385.44 square centimeters.
A circle with a radius of 21 cm has an area of ~1,385.44 square cm
Its just the area of a circle 21 inches or 21 centimeters? area of a circle is (pi)*r2 where pi = 3.1415.... and r = radius thus A = (3.1415)*(diameter/2)2 u can figure out the answer from that with a calculator
Using 3.14 as Pi the area of circle is: 1384.74
A circle with a radius of 21 units has an area of 1,385.44 square units.
Area = pi*212
Using 3.14 as Pi the area of circle is: 1384.74
To find the radius of a circle when given the circumference, you can use the formula for the circumference of a circle: C = 2πr, where C is the circumference and r is the radius. Given that the circumference is 132 cm, you can plug this value into the formula: 132 = 2πr. To solve for the radius, divide both sides by 2π: r = 132 / (2π) ≈ 21 cm. Therefore, the radius of the circle is approximately 21 centimeters.
About 1385.44cm2
If the area is a circle and the radius of the circle is 21 miles, the distance around the circle (circumference) is 131.95 miles. The area of that circle is 1,385.4 square miles.