Triangle Congruence

1. Diliation

1.1. that creates a smaller image is called a reduction. A dilation stretches or shrinks the original figure.

2. Isometry

2.1. a linear transformation which preserves length

3. Rigid Transformation

3.1. is a transformation of the plane that preserves length

4. Acute Triangle

4.1. is a triangle with all three angles acute (less than 90°)

5. Equiangular Triangle

5.1. is a triangle where all three interior angles are equal in measure

6. triangle rigity

6.1. A property of triangles that states that if the side lengths of a triangle are fixed, the triangle can have only one shape.

7. CPCTC

7.1. "Corresponding parts of congruent triangles are congruent"

8. Right Triangle

8.1. Is a triangle that has at least one right angle

9. Obtuse Triangle

9.1. is a triangle in which one of the angles is an obtuse angle

10. Equilateral Triangle

10.1. is a triangle in which all three sides are equal

11. Isosceles Triangle

11.1. is a triangle with (at least) two equal sides

12. Scalene Triangle

12.1. is a triangle that has three unequal sides

13. auxiliary line

13.1. is an extra line needed to complete a proof in plane geometry