Classifying Triangles
The sum of the angles in a triangle is equal to
180 degrees
An exterior angle of a triangle is an angle formed _______ the triangle when one of the sides is extended.
outside
Lines that cross each other at exactly one point are called
Intersecting Lines
An angle is formed by two rays with a common point called the _________.
Vertex
_________________________ ____________ are lines that are at equal distance from each other and never intersect.
Parallel lines
A triangle with 3 congruent sides and 3 congruent angles is classified as
Equiangular/equilateral triangle
What does the Exterior Angle Theorem state?
The exterior angle of a triangle is equal to the sum of the two opposite interior angles of the triangle.
A point on a line segment that divides it into two equal segments is called
Midpoint
An _______ ___________ is a line that divides an angle into two equal parts.
Angle bisector
A line that intersects two or more lines is called a
Transversal
A triangle with 2 congruent sides and 2 congruent angles is classified as
Isosceles triangle
The two opposite interior angles of a triangle measure 36 degrees and 42 degrees. What is the measure of the exterior angle?
78 degrees
Segment AB bisects segment CD. If CD = 6x + 2 and DE = 2x + 4, what is the value of x?
x = 3
Two angles that sum to 180 degrees are called
Supplementary angles
SAME position on parallel lines
SAME side of transversal
What type of angles are these?
Corresponding Angles
A triangle has side lengths of 11.2, 13.2, and 7. It's angle measures are 32 degrees, 58 degrees, and 90 degrees. What triangle(s) can this be classified as?
Right, Scalene
The two opposite interior angles of a triangle measure 6x degrees and 4x degrees. The exterior angle measures 110 degrees. Solve for x, then solve for the missing angles.
x = 11
Missing angles: 66 degrees, 44 degrees
B is the midpoint of segment AC. If BC = 3x + 6 and AC = 8x + 4, find the length of AB.
AB = 18
Segment BD bisects angle ABC. If the measure of angle ABD = x + 40 and the measure of angle CBD = 3x - 20, find the measure of angle ABC.
Measure of angle ABC = 140 degrees
OPPOSITE sides of transversal
INSIDE the parallel lines
“Z Shape”
What type of angles are these?
Alternate Interior Angles
A triangle has side lengths 2.5, 2.5, and 4.5. It's angle measures are 26 degrees, 26 degrees, and 128 degrees. What triangle(s) can this be classified as?
Obtuse, isosceles
The two opposite interior angles of a triangle measure (2x+4) degrees and 2x degrees. The exterior angle measures 120 degrees. Solve for x, then solve for the missing angles.
x = 29
Missing angles: 62 degrees, 58 degrees
M is the midpoint of segment PQ. If PM = 7x + 8 and MQ = 5x + 20, find the length of PM.
PM = 50
If segment BD bisects angle CBE, the measure of angle CBD = 5x and the measure of angle CBE = 8x + 16, find the measure of angle ABC.
Measure of angle ABC = 140 degrees
SAME side of transversal
INSIDE the parallel lines
“C Shape”
What type of angles are these?
Same Side Interior Angles