Please see the pic, I'd solved in it.
Answer:
A
Step-by-step explanation:
A secant is a line that goes through a circle at two points.
Answer:
<abd+<dbc=<Abc
50+40=90
triangle abc is a right angled triangle being one angle 90 degree
Well, what I would do [not sure if it's the correct way], is use the white area as a sector of a circle. The top right of the box is the center of the circle, so the radius is 6.
Then, by the white portion being one quarter of the circle (90° out of 360°), I could calculate the that pink shaded region = the total square (6×6) minus the white sector.
So area (A) of white sector (s): A(s) = 1/4×pi×r^2

36 - 28.27 = 7.73