Circle parts F Area of a circle Formula

Circle parts F

Area of a circle

Formula for the area of a circle We can find the area of a circle using the formula Area of a circle = π × r radius or Area of a circle = πr 2

The area of a circle Use π = 3. 14 to find the area of this circle. 4 cm A = πr 2 = 3. 14 × 4 = 50. 24 cm 2

Find the area of this shape Use π = 3. 14 to find area of this shape. The area of this shape is made up of the area of a circle of diameter 13 cm and the area of a rectangle of width 6 cm and length 13 cm. 6 cm 13 cm Area of circle = 3. 14 × 6. 52 = 132. 665 cm 2 Area of rectangle = 6 × 13 = 78 cm 2 Total area = 132. 665 + 78 = 210. 665 cm 2

The area of a circle Use π = 3. 14 to find the area of the following circles: 2 cm A = πr 2 10 m A = πr 2 23 mm A = πr 2 78 cm A = πr 2

The circumference of a circle For any circle, circumference π= diameter or, C π= d We can rearrange this to make an formula to find the circumference of a circle given its diameter. C = πd

The circumference of a circle Use π = 3. 14 to find the circumference of this circle. 8 cm C = πd = 3. 14 × 8 = 25. 12 cm

The circumference of a circle Use π = 3. 14 to find the circumference of the following circles: 4 cm C = πd 23 mm 9 m 58 cm C = πd

Find the perimeter of this shape Use π = 3. 14 to find perimeter of this shape. The perimeter of this shape is made up of the circumference of a circle of diameter 13 cm and two lines of length 6 cm 13 cm Perimeter = 3. 14 × 13 + 6 = 52. 82 cm