Circumference of a circle =2πr Diameter =2× radius =2r ⇒ Circumference =π× diameter π=22∕7 Circumference =88 ⇒88=22∕7× diameter Multiply both sides by 7 88×7=22× diameter Divide both sides by 22 88×7∕22= diameter NOTE: 22 goes into 88, 4 times 4×7= diameter 28= diameter ⇒ the diameter is 28 cm