What type of math is this?
Since this is a percentage, all you have to do is divide 21 from 80 and multiply that by 100
21/80 = .2625 * 100 is 26.25
The answer closest to this is 25%, so the answer is 25%
Hope this helped! :D
It should be noted that the angle at the center of the circle is twice the angle at the circumference.
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Circle Theorem</h2>
It should also be noted that the angle in a semicircle is a right angle. Angles that are in the same segment are equal.
Furthermore, the opposite angle that is in a cyclic quadrilateral sum is 180°. The angle between the chord and the tangent is also equal to the angle in the alternate segment.
Learn more about circles on:
brainly.com/question/24375372