As shown in the figure is a cross section of a machine part drawn on a scale of 1:20. Please measure the radii of the two circles in the figure and calculate the actual cross section area of the part

As shown in the figure is a cross section of a machine part drawn on a scale of 1:20. Please measure the radii of the two circles in the figure and calculate the actual cross section area of the part

The radius of the circle is 2 cm and 1 cm respectively, then 2 △ 120 = 40 (CM), 1 △ 120 = 20 (CM), 3.14 × (402-202), = 3.14 × (1600-400), = 3.14 × 1200, = 3768 (square cm); answer: the actual area of the cross section of this part is 3768 square cm