Page No 366:
Question 7:
Find the area of the smaller part of the circle x2 + y2 = a2 cut off by the line 
The area of the smaller part of the circle, x2 + y2 = a2, cut off by the line, , is the area ABCDA.
It can be observed that the area ABCD is symmetrical about x-axis.
∴ Area ABCD = 2 × Area ABC
Therefore, the area of smaller part of the circle, x2 + y2 = a2, cut off by the line, , is 
units.
