Huanggang Small Champion Exercise Book R Edition Primary School Mathematics Grade Six Volume I Page 43 Calculation of Heaven's Fourth Major Problem Second Minor Problem
Circumference: 2x3.14x40.125 = 3.14 (cm) 3.14x4 ÷ 2 = 6.28 (cm) 3.14+6.27.
Area: 3.14x16x0.125 = 6.28 (cm? )4x2÷2=4(cm？ )6.28-4=2.28(cm？ )