Solve for each indicated angle measure or variable in the figure.
m x

If vertical angles are congruent you know

84=4x
21=x

You also know that angle M is supplementary to the angle
, measuring 84. Supplementary means it adds to 180 so if you take the difference you get

180-84=M
96=M

Also M is vertical to the last unknown angle so since vertical angles are congruent the last angle is also 96

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