When two angles have the same number of markers, this indicates that the angles are congruent.
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Practice makes perfect
On the diagram, the angle markers indicate congruent angle pairs.
∠ L&≅ ∠ Z
∠ M&≅ ∠ Y
Two angles of △ MLN are congruent to two angles of △ YZX.
According to the Third Angles Theorem, this means that the third angles of the two triangles are also congruent.
∠ N ≅∠ X
An expression for the measure of ∠ X is given. We can use the Triangle Angle-Sum Theorem in △ MLN to set up and solve an equation for x.
