Diameter of circle = side length of square,
Radius of circle = length of square side ÷2
Shadow area 1= square area-circular area.
=40- (square side length ÷2)x (square side length ÷2)x3. 14
=40- (square side length x square side length) ÷2÷2x3. 14
=40-40÷2÷2x3. 14
=8.6 (square centimeter)
2,
Diameter of circle = diagonal length of square,
Radius of circle = diagonal length of square ÷2
Shadow area 2= circular area-square area
= (square diagonal length ÷2)x (square diagonal length ÷2)x3. 14-40
= (square diagonal length x square diagonal length) ÷2÷2x3. 14-40
= (square side length x square side length x square side length) ÷2÷2x3. 14-40, Pythagorean theorem
=(40+40)÷2÷2x3. 14-40
=22.8 (square centimeter)
Shadow area 2 is greater than 1: 22.8-8.6= 14.2 (square centimeter).