The unknown angles are as follows;
x = 180 degrees
r = 90 degrees.
How to find the angles of each value in a circle?
The angle subtended by an arc of a circle at its centre is twice the angle it subtends anywhere on the circle's circumference.
Therefore,
x = 2(90)
x = 180
Therefore, the sum of angle in a circle is 360 degrees.
Hence, the 2 angles of the arc are the same.
Therefore,
360 - 180 = 2r
2r = 180
divide both sides by 2
2r / 2 = 180 / 2
r = 90 degrees.
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