Vertical angles lie diagonally opposite one another at an intersection. Vertical angles are always equal in measure. When angles are equal in measure, we ...
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Have learners draw intersecting lines on the board. Ask, “Which angles look equal? How could we prove they are equal?”
Use objects around the room (pencils, rulers, yardsticks) to have learners create congruent angles.
When two lines lie on a flat surface, they are parallel or else they intersect at some point. Parallel lines never meet or intersect. They remain an equal distance apart no matter how far they are extended.
On the other hand, intersecting lines do cross. When intersecting lines cross, they form four pairs of supplementary angles. A supplementary angle is formed when the sum of the measures of two angles equals 180o. At the intersection, the angles that lie diagonally opposite one another are called vertical angles. Vertical angles are always equal in measure. When angles are equal in measure, we say they are congruent.
- For what professions would you need to measure angles?
- Can you think of examples of vertical and congruent angles you see every day?
- In your everyday life, when would you need to apply what you know about vertical and congruent angles?
Common Core State Standards
CCSS.Math.Con.HSG-CO (High School - Geometry ): Congruence
CCSS.Math.Con.HSG-CO.A (High School - Geometry ): Experiment with transformations in the plane
- CCSS.Math.Con.HSG-CO.A (High School - Geometry ): Experiment with transformations in the plane