# Area Of Circle By Diameter

Area Of Circle By Diameter. Given the radius of a circle, find its area. For example, if the radius is 5 inches, then using the first area formula calculate π x 5 2 = 3. 14159 x 25 = 78. 54 sq in. Find the area of a circle given its diameter is 12 cm. Apply the second equation to get π x (12 / 2) 2 = 3. 14159 x 36 = 113. 1 cm 2 (square centimeters).

This result is the circle's radius of 15. 9 centimeters. Multiply the radius with itself, getting the square, in our case 256 cm². Multiply by π, or 3. 14 for an estimation. A circle with a circumference of 1 meter has an area of 795. 78 cm². Area and circumference formula. Circumference (the distance around the circle) is found with this formula: C = 2πr c = 2 π r. That means we can take the circumference formula and solve for r r , which gives us: R = c 2π r = c 2 π.