Vertical Angles |
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Vertical Angles are congruent. |

Figure 1. |
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When two lines intersect, the vertical angles are congruent. In this case, angles 1 / 4 and angles 2 / 3 are congruent.

Adjacent Angles |
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Angles that share the same vertex and a common side are called Adjacent Angles. |

Figure 2. |
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Above we have an example of two adjacent angles.

Complementary Angles |
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Two angles are Complementary Angles if they sum to 90 degrees. |

Figure 3. |
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Above we have an example of two complementary angles.

Supplementary Angles |
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Two angles are Supplementary Angles if they sum to 180 degrees. |

Figure 4. |
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Above we have an example of two supplementary angles.