Download Quarter 3 Justifications: OLD Right Angles Congruence Theorem

Quarter 3 Justifications:
OLD
Right Angles Congruence Theorem
Vertical Angles Congruence Theorem
Alternate Interior Angles Theorem (and Converse)
Corresponding Angles Theorem (and Converse)
Definition of Congruence
Definition of Midpoint
Definition of Segment Bisector
Definition of Angle Bisector
Definition of Supplementary
Reflexive Property
CHAPTER 5
5.1 Triangle Sum Theorem: The sum of the measures of the interior angles of a triangle is 180°.
5.2 Exterior Angle Theorem: The measure of an exterior angle of a triangle is equal to the sum of the
measures of the two nonadjacent interior angles
Corollary 5.1 Corollary to the Triangle Sum Theorem: The acute angles of a right triangle are
complementary.
5.3 Properties of Triangle Congruence: Triangle congruence is reflexive, symmetric, and transitive.
Reflexive: For any triangle △ABC, △ABC ≅ △ABC.
Symmetric: If △ABC ≅ △DEF, then △DEF ≅ △ABC.
Transitive: If △ABC ≅ △DEF and △DEF ≅ △JKL, then △ABC ≅ △JKL.
5.4 Third Angles Theorem: If two angles of one triangle are congruent to two angles of another triangle,
then the third angles are also congruent.
5.5 Side-Angle-Side (SAS) Congruence Theorem: If two sides and the included angle of one triangle are
congruent to two sides and the included angle of a second triangle, then the two triangles are
congruent.
5.6 Base Angles Theorem: If two sides of a triangle are congruent, then the angles opposite them are
congruent.
5.7 Converse of the Base Angles Theorem: If two angles of a triangle are congruent, then the sides
opposite them are congruent.
Corollary 5.2 Corollary to the Base Angles Theorem: If a triangle is equilateral, then it is equiangular.
Corollary 5.3 Corollary to the Converse of the Base Angles Theorem: If a triangle is equiangular, then it is
equilateral.
5.8 Side-Side-Side (SSS) Congruence Theorem: If three sides of one triangle are congruent to three sides
of a second triangle, then the two triangles are congruent.
5.9 Hypotenuse-Leg (HL) Congruence Theorem: If the hypotenuse and a leg of a right triangle are
congruent to the hypotenuse and a leg of a second right triangle, then the two triangles are congruent.
5.10 Angle-Side-Angle (ASA) Congruence Theorem: If two angles and the included side of one triangle
are congruent to two angles and the included side of a second triangle, then the two triangles are
congruent.
5.11 Angle-Angle-Side (AAS) Congruence Theorem: If two angles and a non-included side of one triangle
are congruent to two angles and the corresponding non-included side of a second triangle, then the two
triangles are congruent.
CPCTC: Corresponding parts of congruent triangles are congruent.
CHAPTER 7
7.1 Polygon Interior Angles Theorem: The sum of the measures of the interior angles of a convex n-gon
is (n − 2) ⋅ 180°.
Corollary 7.1 Corollary to the Polygon Interior Angles Theorem: The sum of the measures of the interior
angles of a quadrilateral is 360°.
7.2 Polygon Exterior Angles Theorem: The sum of the measures of the exterior angles of a convex
polygon, one angle at each vertex, is 360°.
7.3 Parallelogram Opposite Sides Theorem: If a quadrilateral is a parallelogram, then its opposite sides
are congruent.
7.4 Parallelogram Opposite Angles Theorem: If a quadrilateral is a parallelogram, then its opposite
angles are congruent.
7.5 Parallelogram Consecutive Angles Theorem: If a quadrilateral is a parallelogram, then its consecutive
angles are supplementary.
7.6 Parallelogram Diagonals Theorem: If a quadrilateral is a parallelogram, then its diagonals bisect each
other.
7.7 Parallelogram Opposite Sides Converse Theorem: If both pairs of opposite sides of a quadrilateral
are congruent, then the quadrilateral is a parallelogram.
7.8 Parallelogram Opposite Angles Converse Theorem: If both pairs of opposite angles of a quadrilateral
are congruent, then the quadrilateral is a parallelogram.
7.9 Opposite Sides Parallel and Congruent Theorem: If one pair of opposite sides of a quadrilateral are
congruent and parallel, then the quadrilateral is a parallelogram.
7.10 Parallelogram Diagonals Converse Theorem: If the diagonals of a quadrilateral bisect each other,
then the quadrilateral is a parallelogram.
Corollary 7.2 Rhombus Corollary: A quadrilateral is a rhombus if and only if it has four congruent sides.
Corollary 7.3 Rectangle Corollary: A quadrilateral is a rectangle if and only if it has four right angles.
Corollary 7.4 Square Corollary: A quadrilateral is a square if and only if it is a rhombus and a rectangle.
7.11 Rhombus Diagonals Theorem: A parallelogram is a rhombus if and only if its diagonals are
perpendicular.
7.12 Rhombus Opposite Angles Theorem: A parallelogram is a rhombus if and only if each diagonal
bisects a pair of opposite angles.
7.13 Rectangle Diagonals Theorem: A parallelogram is a rectangle if and only if its diagonals are
congruent.
7.14 Isosceles Trapezoid Base Angles Theorem: If a trapezoid is isosceles, then each pair of base angles is
congruent.
7.15 Isosceles Trapezoid Base Angles Converse Theorem: If a trapezoid has a pair of congruent base
angles, then it is an isosceles trapezoid.
7.16 Isosceles Trapezoid Diagonals Theorem: A trapezoid is isosceles if and only if its diagonals are
congruent.
7.17 Trapezoid Midsegment Theorem: The midsegment of a trapezoid is parallel to each base, and its
length is one-half the sum of the lengths of the bases.
7.18 Kite Diagonals Theorem: If a quadrilateral is a kite, then its diagonals are perpendicular.
7.19 Kite Opposite Angles Theorem: If a quadrilateral is a kite, then exactly one pair of opposite angles
are congruent
CHAPTER 8
8.1 Perimeters of Similar Polygons Theorem: If two polygons are similar, then the ratio of their
perimeters is equal to the ratios of their corresponding side lengths.
8.2 Areas of Similar Polygons Theorem: If two polygons are similar, then the ratio of their areas is equal
to the squares of the ratios of their corresponding side lengths.
8.3 Angle-Angle (AA) Similarity Theorem: If two angles of one triangle are congruent to two angles of
another triangle, then the two triangles are similar.
8.4 Side-Side-Side (SSS) Similarity Theorem: If the corresponding side lengths of two triangles are
proportional, then the triangles are similar.
8.5 Side-Angle-Side (SAS) Similarity Theorem: If an angle of one triangle is congruent to an angle of a
second triangle and the lengths of the sides including these angles are proportional, then the triangles
are similar.
8.6 Triangle Proportionality Theorem: If a line parallel to one side of a triangle intersects the other two
sides, then it divides the two sides proportionally.
8.7 Converse of the Triangle Proportionality Theorem: If a line divides two sides of a triangle
proportionally, then it is parallel to the third side.
8.8 Three Parallel Lines Theorem: If three parallel lines intersect two transversals, then they divide the
transversals proportionally.
8.9 Triangle Angle Bisector Theorem: If a ray bisects an angle of a triangle, then it divides the opposite
side into segments whose lengths are proportional to the lengths of the other two sides.
CPSTS: Corresponding parts of similar triangles are similar.