Download Angles of Triangles VOCABULARY Interior angles

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CHAPTER 3 STUDY GUIDE
LINES
A
B
C
Lines: extend forever in both directions and are written like: AB,
BC,
AC
Rays: extend forever in one direction and have one endpoint. They are written like: BD
Segments: part or a piece of the line. Do not extend at all. They are written like:
AB,
BC,
ANGLES
Adjacent: angles that are next to each other, share a vertex (corner) and a side
Vertical: formed by two intersecting lines (crisscross) and have the same measure
Congruent: same measure
Supplementary: two angles together that form a straight line (180 degrees)
Complementary: two angles together that form a corner (right angle, 90 degrees)
Transversals: a line that intersects two other lines
Corresponding angles: lie on the same side of the transversal and have the same measure
Alternate interior: on the inside, but on opposite sides of the transversal, has the same measure
Alternate exterior: on the outside on opposite sides of the transversal, has the same measure
AC,
BD
Angles of Triangles
VOCABULARY
Interior angles: angles inside the polygon
Exterior angles: angles outside the polygon that are adjacent to the interior angles
Interior triangle angles = 180°
Straight lines = 180°
Steps:
1.Write an equation
2.Solve for the variable
48 + 87 + x = 180
60 + 7x + 5 = 20x
The remote angles = the exterior
angle
Find x then sub in to find the angle
measure
To find the total interior angle measures of a polygon
1.
count the sides
2.
Subtract 2
3.
Multiply by 180
( s  2)  180  total