### congruent polygon

two figures that have the same size and shape such that their vertices can be matched up so corresponding parts ( angles and sides) of the figure are congruent

### perpendicular bisector

a line, ray, or segment that is perpendicular to a side of the triangle at its midpoint

### distance from a point to a line

the length of the perpendicular segment from the point to the line or plane

### sss

If three sides of one triangle are congruent to three sides of another triangle, then the triangles are congruent.

### SAS

If two side and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the triangles are congruent.

### ASA

If two angles and the included side of one triangle are congruent to two angles and the include side of another triangle, then the triangles are congruent.

### Isosceles triangle theorem

If two sides of a triangle are congruent, then the angles opposite those sides are congruent.

Corollary 1: An equilateral triangle is also equiangular

Corollary 2: An equilateral triangle has three 60 degree angles

Corollary 3: The bisector of the vertex angle of an isosceles triangle is perpendicular to the base ate its midpoint

### AAS

If two angles and a non-inclulded side of one triangle are congruent to the corresponding parts of another triangle, then the triangles are congruent

### HL Thereom

If the hypotenuse and a leg of one right triangle are congruent to the corresponding parts of another right triangle, then triangles are congruent

### 4-5

If a point lies on the perpendicular bisector of a segment, then the point is equidistant from the endpoints of the segment

### 4-6

If a point is equidistant from endpoints of a segment, then the point lies on the perpendicular bisector of the segment

### 4-7

If a point lies on the bisector of an angle, then the point is equidistant from the sides of the angle