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)
The radius of the circle is 21 inches. The area of the circle is (pi) times (radius squared) = pi times 441 = 1,385.44+ square inches. 1 square foot = 144 square inches. The area of the circle is (1385.44+ square inches) divided by 144 = 9.621 square feet (rounded to 3 decimal places).
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.