Roll a piece of rectangular paper 12.56 cm long and 6.28 cm wide into the largest cylinder. What is the volume of the cylinder in cubic centimeter? (excluding joints)

Roll a piece of rectangular paper 12.56 cm long and 6.28 cm wide into the largest cylinder. What is the volume of the cylinder in cubic centimeter? (excluding joints)

12.56 △ 3.14 △ 2 = 2 (CM); 3.14 × 22 × 6.28, = 3.14 × 25.12, = 78.8768 (cm3); 6.28 △ 3.14 △ 2 = 1 (CM); 3.14 × 12.56, = 3.14 × 12.56, = 39.4384 (cm3); 78.8768 cm3 > 39.4384 cm3