# Circle

Calculate the second moment of area (also known as moment of inertia of plane area, area moment of inertia, or second area moment) and the section modulus of a profile with circular cross section and diameter A. Use this to calculate deflection or stress in a loaded profile.

$$I_{yy} = \dfrac {πA^{4}}{64}$$

$$I_{p} = \dfrac {πA^{4}}{32}$$

$$W_{yy} = \dfrac {πA^{3}}{32}$$