Answer
m$\angle$3=60$^{\circ}$
Work Step by Step
m$\angle$3=.5(RST-RT)
m$\angle$3=.5(240-120)
m$\angle$3=.5(120)
m$\angle$3=60$^{\circ}$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.