As can be seen from the figure, the height of parallelogram is higher than the radius of circle; The number of adjacent angles of a 45-degree parallelogram is equal to the degree of the blank central angle, and the degree of the central angle of the shaded part is equal to 360 minus the degree of the blank central angle. According to these two conditions, they are substituted into the sector area formula (n π r 2).

Go inside. Pi?

Calculation: 40 degrees

10=4

360-(360-45×2)÷

2=360- 135=225 degrees

225π

10^

2÷

360= 196.25 cm2