Geometry Reflective Portfolio
Unit #4: Triangle Angles
All study portfolios need to be kept in one folder!!Keep it neat and organized!!!!
Section #1: Vocabulary (words and/or labeled diagrams)
Exterior angle of a triangle
Centroid
Circumcenter
Incenter
Median
Isosceles Triangle
Isosceles Triangle-draw, and
label the parts (vertex angle,
base angles, legs, base)
Section #2: Formulas/Equations /Theorems (write the theorems filling in the blanks)
Midpoint formula:
`
Centroid formula:
Isosceles Triangle Theorems
 Isosceles Triangle Base Angles Theorem – If a triangle has 2 congruent sides, then
_____________________.
 Converse Isosceles Triangle Base Angles Theorem – If a triangle has 2 congruent angles,
then _________________________.
 Isosceles Triangle Symmetry Theorem - The line containing the bisector of the vertex angle
of an isosceles triangle is a _________ line for the triangle.
 Isosceles Triangle Coincidence Theorem - In an isosceles triangle, the bisector of the
vertex angle, the perpendicular bisector of the base, and the median to the base determine
the _______________.
Triangle Sum of Interior Angle theorems
 The sum of the interior angles of a triangle is __________.
Triangle Exterior Angle theorems
 The measure of the exterior angle of a triangle is the sum of the two
_______________________________________________________________________.
 The sum of the measures of an exterior angle and its adjacent interior angle is ________.
 The sum of the measures of all three exterior angles is _____________.
Triangle Inequality Theorems
 The sum of every two sides must be __________________________________________.
 The exterior angle of a triangle is greater than __________________________________.
 The largest angle of a triangle is opposite the ___________________________________.
 The shortest side is opposite the _____________________________________________.
Section #3: Key methods and concepts (write out the process and/or a solved example)
 What are the triangle classifications by angles and sides?
Angles
Sides

What are the steps to finding the equation of a perpendicular bisector given two points AND
use that process on the following example: (2, 0) and (6, 4).
Clearly organize the steps and show the work for this example!!

How do you divide a segment into “n”
equal parts using slope?
Use A(-4,7) and J(8,3) divide AJ into 4 equal
segments

How do you divide a segment into a
givenratio?
Now find the point on BC ; B( 1,-5) and
C( (9,-1) that is 2/3 the way from B to C.
New Construction:
Use a compass and straightedge:
 How do you divide a segment into “n” equal parts using constructions?
Show how to divide this segment into 3 equal parts.