Transform 16 Sectors The Area of a CircleĪs the number of sectors  , the transformed shape becomes more and more like a rectangle. 3 4 8.5 cm 6 cm C =d C =2r Perimeter =¾(2r) + 2r = ¾ x 2 x  x 8.5 + 2 x 8.5 = 57.1 cm (1 dp) Perimeter =¼(2r) + 2r = ¼ x 2 x  x 6 + 2 x 6 = 21.4 cm (1 dp)Ĭ =d C =2r The Circumference of a Circle Find the diameter/radius of the following circles. The Circumference of a Circle Find the perimeter of the ¼ and ¾ circles.

The Circumference of a Circle Find the perimeter of the following semi-circles.

4 3 3 mm C =d 2.1 m C =2r C =2r C = 2 x  x 3 C = 18.8 mm(1 dp) C = 2r C = 2 x  x 2.1 C = 13.2 m(1 dp)įind the circumference of the tyre and steering wheel. The Circumference of a Circle Find the circumference of the following circles. The Circumference of a Circle It’s the same for all circles! 1 1½ 2 2½ 3 3½ 4 d diameter(d) In terms of the radius: radius C =? Circumference (C)  = 1 2 C =2r 3 The Circumference of a Circle How many times does the diameter fit around the circumference? Choose your number.

Circumference of a circle