Angle 1 is 20 degrees.
Calculate the size of angle 2.
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Angle 1 is 20 degrees.
Calculate the size of angle 2.
Remember the definition of vertically opposite angles:
Vertically opposite angles are formed between two intersecting lines, and they actually have a common vertex and are opposite each other. Vertically opposite angles are equal in size.
Therefore:
If one of two corresponding angles is a right angle, then the other angle will also be a right angle.
Vertically opposite angles are formed when two lines intersect. They share the same vertex (intersection point) and point in opposite directions - like angle 1 and angle 2 in this problem.
When two lines cross, they create four angles. The angles across from each other are mirror images, so they must have the same measure. It's a geometric law!
Look for angles that are across from each other at an intersection point. They don't share a side - there's empty space between them. In this diagram, angles 1 and 2 are on opposite sides of where the lines cross.
No! That would make angles 1 and 2 supplementary (adding to 180°). But supplementary angles are adjacent (next to each other), not vertically opposite. Since angle 1 = 20°, angle 2 must also equal 20°.
Focus on identifying the vertex (where lines meet) and trace which angles are directly across from each other. Even in complex diagrams, vertically opposite angles will always be equal.
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