Question

find x.
3x°
120°

a. 40
b. 20
c. -10
d. 90

Explanation:

Step1: Recall the property of tangents and central - angle

The measure of the angle formed by two tangents to a circle is supplementary to the central - angle intercepted by the arc between the points of tangency. So the angle formed by the two tangents is $180^{\circ}- 120^{\circ}=60^{\circ}$.

Step2: Set up an equation for $x$

We know that the given angle is $3x$. So we set up the equation $3x = 60$.

Step3: Solve the equation for $x$

Dividing both sides of the equation $3x = 60$ by 3, we get $x=\frac{60}{3}=20$.

Answer:

B. 20