A =  r 2 A =  x 8 2 A = cm 2 (1 dp) A =  r 2 A =  x A = cm 2 (1 dp) The Area of a Circle Find the area of the following circles. A =  r 2 8 cm cm 2

The Area of a Circle Find the area of the following circles. 6 mm m 4 A =  r 2 A =  x 3 2 A = 28.3 mm 2 (1 dp) A =  r 2 A =  x A = 4.5 m 2 (1 dp) A =  r 2

Find the area of the clock face and radar screen. 60 cm 12 cm A =  r 2 A =  x 12 2 A = cm 2 (1 dp) A =  r 2 A =  x 30 2 A = 2827 cm 2 (nearest cm 2 )

The Area of a Circle Find the area of the following semi-circles. 8 cm cm 2 A = ½  r 2 = ½ x  x 4 2 = 25.1 cm 2 (1 dp) A = ½  r 2 = ½ x  x = 35.4 cm 2 (1 dp) A =  r 2

A = ¼  r 2 = ¼ x  x 6 2 = 28.3 cm 2 (1 dp) A = ¾  r 2 = ¾ x  x = cm 2 (1 dp) The Area of a Circle Find the area of the ¼ and ¾ circles cm 8.5 cm A =  r 2

 r 2 = 25 r 2 = 25/  r =  (25/  ) r = 2.82 d = 2 x 2.82 = 5.6 cm 1dp A =  r 2 The Area of a Circle Find the radius/diameter of the following circles. A = 25 cm 2 find the diameter. 6 5 A = 30 cm 2 find the radius.  r 2 = 30 r 2 = 30/  r =  (30/  ) r = 3.1 cm 1dp