1,017.9 cm2
Using 3.14 as Pi the area of circle is: 1017.36
The general equation for the area of a circle is π*r2, where r is the radius of the circle, and π is pi, which is approximately 3.14159. The diameter of a circle is how far it is from one side of the circle to the other, and the radius is how far it is the from edge to the center, thus the radius is half the diameter. Therefore the area is π*(92) ~ 254.47
9 cm (r = d/2)
A = 254.47 cm2
The perimeter is pi*r + 2r = 92.6 cm
The diameter is always double the radius so in this case, it is 18cm
A sector with a radius of 2 cm can't have an arc of 18 cm. If the radius is 2 cm, then the entire circumference of the whole circle is a little less than 12.6 cm. Strange as it may seem, the area of that whole circle is a little less than 12.6 cm2 .
SA = 904.78 cm2
The radius of a circle is half of its diameter. If the diameter is 18 cm, then the radius would be 18 cm divided by 2, which equals 9 cm. Thus, the radius is 9 cm.
The area of a circle with a radius of 14.4 is 651.4
Area of a circle = pi*radius squared
The area of a circle of radius 21 is 1386