Geometry

1. Lie perpendicular to another segment. It crosses at the midpoint.
3. If a point is an angle bisector, then it is equidistance to the side of the angle. The angle bisector cuts the angle in half.
8. The circumcenter is equidistance from each vertex of the triangle. The circumcenter is the point of concurrency for perpendicular bisectors.
9. Congruent sides of isosceles triangle. Also, occurs in trapezoids.
12. All parts of one polygon are the same shape and same size. To corresponding parts of another polygon.
13. If two sides of a triangle are congruent, then angles opposite are congruent. If the legs of the triangle are congruent then base angles are congruent.
16. The original figure and the transformed image are still congruent. The triangle reflected across the y-axis is still congruent to the original triangle.
17. If two sides of a triangle are congruent to two sides of another triangle and the included angle of the first triangle is larger than that of the second triangle. Then the third side of the first triangle is langer than the third side of the second triangle.
18. Angles of a triangle add up to 180 degrees. A+B+C=180
20. Angles that lie between two transversals that intersect the same line. Two angles that are opposite from the Exterior Angle.
21. The measure of an exterior angle of a triangle is equal to the sum of the remote interior angles. Exterior angle=remote interior angles

2. The centroid is 2/3 of the distance from each vertex to the midpoint on the opposite side. Centroid is the point of concurrency for medians.
4. An angle formed by one side of a triangle and the extension of another side. Two remote interior angles add up to equal this angle.
5. If two angles of a triangle are congruent, then the sides opposite are congruent. This states if base angles are congruent then the legs are congruent.
6. If the point is on the bisector, then it is equidistant to the endpoints of segments. A point is equidistant from other points if it is the same distance from them.
7. Indirect reasoning with proof to temporarily assume that what we are trying to prove is false. We assume the conclusion is false and then show that assumption led to a contradiction.
10. When three or more lines intersect at a common point. This intersection point is called the point of concurrency.
11. A statement that can be easily proved using a theorem is called a corally of that theorem. Follows with a proof that follows as a direct result of a theorem.
14. All sides are congruent and all angles are congruent. It is also an equiangular triangle.
15. Are matching parts such as sides and angles. There are these in Congruent Polygons.
19. They have the same size and same shape. They are equal and the same.