Vocabulary Geometry Flashcards
The sum of all 3 triangle is 180 degrees
Triangle Sum Theorem
If two sides of a triangle are congruent, then the angels opposite those sides are congruent
Isosceles Triangle Theorem
If two angels of a triangle are congruent, then the sides opposite those sides are congruent
Converse of the Isosceles Triangle Theorem
A triangle with no congruent sides
Scalene Triangle
A triangle with 3 congruent sides
Equilateral triangle
A triangle with 3 congruent angles
Equiangular Triangle
The measures of each exterior angle of a triangle equals the sum of its two remote interior angles
Exterior Angle Theorem
If a line bisects the vertex angle of an isosceles triangle, then the line is also the perpendicular bisector of the base
Angle Bisector of an Isosceles Triangle Theorem
If two angles form a linear pair, then they are supplementary.
Linear Pair Postulate
Vertical angles are congruent
Vertical Angle Theorem
Two lines that intersect to form right angles
Perpendicular Lines
If two lines cut by a transversal are parallel, then the alternate interior angles are congruent
Alternate Interior Angle Theorem
If two line are cut by a transversal and the alternate interior angles are congruent, then the lines must be parallel.
Converse of the Alternate Interior Angle Theorem
for any angle, the measure of the whole is equal to the sum of the measures of its non-overlapping parts
Angle Addition Postulate
The point of concurrency located 2/3 the distance from the vertex
centroid
The longest side is opposite the largest angle
Opposite Side Inequality Theorem
The measure of the exterior angle of a triangle is greater than either of its corresponding remote interior angles
Exterior Angle Inequality Theorem
The sum of the lengths of any two sides of a triangle is greater than the length of the third side.
Triangle Inequality Theorem
an equation that states two ratios are equal
Proportion
the common ratio of corresponding sides
Scale Factor
A point on a segment that divides the segment into 2 congruent segments.
Midpoint
the perpendicular drawn from the vertex of the triangle to the opposite side
(Look at number 22 on paper)
Altitude
a line segment that joins a vertex to the mid-point of the side that is opposite to that vertex
(Look at number 23 on paper)
Median
the line or line segment that divides the angle into two equal parts
(Look at number 24 on paper)
Angle Bisector
lines passing through the midpoint of each side which are perpendicular to the given side.
(Look at number 25 on paper)
Perpendicular Bisector
