Answer: option c. measure of the central angle
Explanation:
1) The ratio of the area of a sector of a circle to the area of th entire the circle is proportional to the ratio of the central angle to 360°.
This is:
ratio of areas = ratio of the angles
ratio of area = area of the sector / area of the circle
ratio of the angles = central angle / 360°
2) Set the proportion with the unnknown:
Area of the sector central angle
------------------------- = ---------------------
Area of the circle 360°
x central angle
------------------------ = --------------------------
area of the circle 360°
3) Solve for x:
x = area of the circle * central angle / 360°
Which is what the option c, tells and that is the answer.
4) The last part of the question, just states that you have to subtract the area of the triangle, just because it is not shaded