Circumference and Area

The area A of a circle is given by the formula A = πr², where r is the radius.

The circumference C of a circle is given by the formula C = 2πr or C = πd, where r is the radius and d is the diameter.

The area is A = π(5)² = 25π or approximately 78.54.

The circumference is C = πd = π(10) = 10π or approximately 31.42.

The diameter d of a circle is twice the radius r, so d = 2r.

To convert diameter to radius, divide the diameter by 2: r = d/2.

The area is A = π(3)² = 9π or approximately 28.27.

The circumference is C = 2π(7) = 14π or approximately 43.98.

The value of π is approximately 3.14.

Using C = 2πr, the radius r = C/(2π) = 31.4/(2π) = 5.