Question

If m ad=20° and m BC =30°,then <1=

Answer 1

When two chords intersect inside a circle, the measure of the angle formed is one half the sum of the measures of the arcs intercepted by the angle and its vertical angle. Then:

`m\angle1=(1)/(2)(mAD+mBC)`

Substitute mAD=20° and mBC=30°:

`\begin{gathered} \Rightarrow m\angle1=(1)/(2)(20+30) \\ =(1)/(2)(50) \\ =25 \end{gathered}`

Therefore, the answer is:

`25^(\circ)`