The cross-section of a steel pipe is annular, the diameter of the outer circle is 12 cm, and the wall thickness of the pipe is 2 cm. What is the cross-sectional area of the steel pipe

The cross-section of a steel pipe is annular, the diameter of the outer circle is 12 cm, and the wall thickness of the pipe is 2 cm. What is the cross-sectional area of the steel pipe

3.14*（6*6-4*4）= 62.8

There is a seamless steel pipe with a circular cross section. The radius of the inner circle is 3cm and the radius of the outer circle is 4cm. What is the cross-sectional area of this steel pipe

4^2*3.14-3^2*3.14
=(4^2-3^2)*3.14
=7*3.14
=21.98 square centimeter

The cross-sectional area of a steel pipe is a ring, the outer circle radius of the steel pipe is 0.4 m, and the wall thickness of the pipe is 0.02 M. how many square centimeters is its cross-sectional area?

The radius of inner circle: 0.4-0.02 = 0.38 (m) its cross-sectional area is: 3.14 × (0.4 # 178; - 0.38 # 178;) = 3.14 × 0.0156 = 0.048984 (m) # 178; = 489.84 square percent

The cross section of a steel pipe is annular, the radius of inner circle is 5cm, and the diameter of outer circle is 8cm. What is the cross section area of the steel pipe

Cross section of steel pipe = outer circle area inner circle area = (8 ^ 2-5 ^ 2) * π = 39 π≈ 122.46, unit: square centimeter