Emerson is completing a construction of an equilateral triangle inscribed in a circle, as shown below. What should be the next step in his construction?

Construct a line parallel to the line AB that touches the circle at point B.
Draw another arc from point A with the same radius as his original circle.
Mark the intersection of the arcs and the circle to determine the vertices.
Place arcs above and below line AB to show where the triangle sides meet.

Question

Emerson is completing a construction of an equilateral triangle inscribed in a circle, as shown below. What should be the next step in his construction? 

Construct a line parallel to the line AB that touches the circle at point B.
 Draw another arc from point A with the same radius as his original circle.
 Mark the intersection of the arcs and the circle to determine the vertices.
 Place arcs above and below line AB to show where the triangle sides meet.

anonymous · Answer

In ΔRST shown below, segment SU is an altitude:
What property or definition is needed to prove that ΔRUS is similar to ΔSUT?
 Transitive Property of Equality
 Reflexive Property of Equality
 Definition of Supplementary Angles
 Definition of Congruence

anonymous · Answer

In ΔRST shown below, segment SU is an altitude:
What property or definition is needed to prove that ΔRUS is similar to ΔSUT?
 Transitive Property of Equality
 Reflexive Property of Equality
 Definition of Supplementary Angles
 Definition of Congruence