3.9 KiB
Angle Theorems
Transversal Parallel Line Theorems
(TPT)- Alternate Angles are Equal
(Z-Pattern)
- Corresponding Angles Equal
(F-Pattern)
- Interior Angles add up to 180
(C-Pattern)
- Alternate Angles are Equal
Supplementary Angle Triangle
(SAT)
Opposite Angle Theorem (OAT)
(OAT)
Complementary Angle Theorem
(CAT)
Angle Sum of a Triangle Theorem
(ASTT)
Exterior Angle Theorem
(EAT)
- The measure of an exterior angle is equal to the sum of the measures of the opposite interior angles
Isosceles Triangle Theorem
(ITT)
Sum of The Interior Angle of a Polygon
The sum of the interioir angles of any polygon is
180(n-2)
or180n - 360
, wheren
is the number of sides of the polygon
Exterior Angles of a Convex Polygon
Congruency
Congruent
: Same size and shape
Side-Side-Side (SSS)
If three sides of a triangle are respectively equal to the three sides of another triangle, then the triangles are congruent
Side-Angle-Side (SAS)
If two sides and the contained angle of a triangle are respectively equal to two sides and the contained angle of another triangle, then the triangles are congruent.
Angle-Side-Angle (ASA)
If two angles and the contained side of a triangle are respectively equal to two angles and the contained side of another triangle, then the triangles are congruent.
Similary Triangles
Similar
: Same shape but different sizes (one is an
enlargement of the other)
Properties
Lets say we have \(`\triangle ABC \sim \triangle DEF`\) 1. Corresponding angles are equal - \(`\angle A = \angle D`\) - \(`\angle B = \angle E`\) - \(`\angle C = \angle F`\)
- Corresponding side are proportional.
- \(`\dfrac{AB}{DE} = \dfrac{AC}{DF} = \dfrac{BC}{EF}`\)
- Proportional Area
- Let \(`k`\) be the scale factor, when concerning for triangle area, if the triangle area can be defined as \(`\dfrac{bh}{2}`\), then by using the smaller triangles side lengths our big triangle’s area is equal to \(`\dfrac{k^2bh}{2}`\). Similar equations and agruments can be dervied from this
Side-Side-Side similarity (RRR \(`\sim`\))
Three pairs of corresponding sides are in the same ratio
Side Angle Side similarity (RAR \(`\sim`\))
Two pairs of corresponding sides are proportional and the contained angle are equal.
Angle-Angle similarity (AA \(`\sim`\))
Two pairs of corresponding angles are equal.