If the radius of the bottom of a cylinder increases by 5 cm, its side area will increase by 125.6 square cm. If the perimeter of the bottom increases by 4 cm, how many square cm will its side area increase?

If the radius of the bottom of a cylinder increases by 5 cm, its side area will increase by 125.6 square cm. If the perimeter of the bottom increases by 4 cm, how many square cm will its side area increase?

125.6 ÷ (2 × 5 × 3.14), = 125.6 ÷ 31.4, = 4 (CM), 4 × 4 = 16 (square cm); a: its side area increases by 16 square cm

If a cylinder with a height of 10 cm is increased by 2 cm, its surface area will increase by 125.6 square cm. What is the circumference of the cylinder

The surface area increases by 125.6 square centimeters, which is equivalent to the side area of a cylinder 2 centimeters high
Side area of cylinder = circumference of bottom surface * height
125.6 △ 2 = 62.8 cm

When the circumference and height of the bottom of the cylinder are equal, the expanded side must be a circle______ ．

According to the analysis: the side of the cylinder is a rectangle, the length of the rectangle is equal to the circumference of the bottom surface of the cylinder, and the width is equal to the height of the cylinder. When the circumference and height of the bottom surface of the cylinder are equal, its side expansion must be square