HURRY! In the diagram of circle O, what is the measure of angle ABC?

Answer: ∠ABC=30°Given: A circle with center O. Two tangents AB and BC are making angle ABC with arc at circle 150°.To find : ∠ABC Solution: We know that the angle formed by the intersection of two tangents outside the circle equals to the half of difference of the intercepted arcs.[major arc and minor arc]From the figure ,Minor arc = 150° Major arc = 360 - 150 = 210° Therefore,∠ABC = [tex]\frac{210^{\circ}-150^{\circ}}{2}=\frac{60^{\circ}}{2}=30^{\circ}[/tex]Thus ∠ABC=30°.