The sum of the degree measures of the angle ABC inscribed in the circle and the central angle AOC is equal to 90 °
The sum of the degree measures of the angle ABC inscribed in the circle and the central angle AOC is equal to 90 °. Calculate: a) the degree measures of the angles ABC and AOC; b) the distance from the center of the circle to the chord AC, if the radius of the circle is 8 cm.
The inscribed angle is half of the central angle resting on the same arc.
Let the inscribed angle ABC = X0, then the central angle AOC = 2 * X0.
By condition, ABC + AOC = 90.
X + 2 * X = 90.
X = ABC = 30, AOC = 60.
In the AOC triangle, OA = OC = R = 8 cm, and the AOC angle = 60, then the AOC triangle is equilateral. The OH segment is the height of an equilateral triangle, then OH = √3 * 8/2 = 4 * √3 cm.
Answer: Angle ABC = 30, angle AOC = 60, distance to the chord is 4 * √3 cm.