Answer:
x = 110°
Explanation:
The Outside Angle Theorem states that the measure of the angle formed by two secants or a secant and tangent from a point outside of a circle is half the difference between the two arcs.
This means that ½ (210 – x) = 50.
½ ( 210 – x ) × 2 = 50 × 2
210 – x = 100.
210 – x + x = 100 + x.
210 = 100 + x.
100 + x = 210.
100 + x – 100 = 210 – 100.
x = 110.
This value must be true because:
½ ( 210 – 110 ) = 50.
½ ( 100 ) = 50.
50 = 50.