| Known Parts | Definition | Able to determine congruency? | Reason |
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| SSS | You know that all three sides of one triangle are equal to the corresponding three sides of another triangle | | |
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| ASS | You know that one angle and two sides which do not include that angle are equal to the corresponding angle and two non-included sides of another triangle | | |
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| SAS | You know that two sides and the angle between those two sides are equal to the corresponding two sides and included angle of another triangle | | |
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| SSA | You know that two sides and a non-included angle are equal to the corresponding two sides and non-included angle of another triangle | | |
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| AAS | You know that two angles and one side not included between those angles are equal to the corresponding two angles and non-included side of another triangle | | |
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| ASA | You know that two angles and the side included between those two angles are equal to the corresponding two angles and included side of another triangle | | |
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| SAA | You know that one side and two angles which do not include that side are equal to the corresponding side and non-included angles of another triangle | | |
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| AAA | You know that all three angles of one triangle are equal to the corresponding three angles of another triangle | | |
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