Geometry Midterm Exam Review - Unit 2

Perpendicular Bisector

A perpendicular segment that goes through the midpoint of another segment

HL

Hypotenuse-leg postulate, can only be used in a right triangle

Altitude

A perpendicular segment that connects a vertex with the side opposite from it

Equilateral Triangle

3 Congruent Sides

Acute Triangle

3 angles that are less than 90 degrees

Median

A segment that connects a vertex with the mid point of the opposite side from it

Equianglular Triangle

All angles are congruent and equal 60 degrees

AAS

Angle-angle-side postulate

ASA

Angle-side-angle postulate

Isosceles Triangle

At least 2 congruent sides

Zero Product Property

If a+b=0, then b=0 or a=0 Want: ax^2 + bx +c = 0

Postulate

If two triangles share the following triplets of congruent corresponding points, then the triangles are congruent

Angle-Side Relationships

In a triangle, the largest side is opposite the largest angle and the smallest side is opposite the smallest angle

Scalene Triangle

No congruent sides

ASS

Not a postulate

Triangle Postulates

SSS, SAS, ASA, AAS and HL

Congruency

Same shape and same size

SAS

Side-angle-side postulate

SSS

Side-side-side postulate

Reflexive Property

Some object is congruent to itself

How to write a congruence proof

Step 1: Mark Diagram Step 2: identify the Postulate Step 3: Organize thoughts Step 4: Write Proof, state the given info first Step 5: Reread Proof

Triangle Inequality

The sum of any 2 sides of a triangle that must be greater than the 3rd side

Right Triangle

has one angle that equals 90 degrees

Obtuse Triangle

has one angle that measures more than 90 degrees