Chapter 1 Flashcards
formed by two rays with the same end point
angle
The common endpoint of an angle is called the
vertex
The rays of an angle are called the
sides
Symbol commonly used to represent an angle
theta θ
Angle θ can also be denoted by AOB, where the letter associated with the vertex is written between the letters associated with the points on each side, so the vertex is
O
When the rotation from the initial side to the terminal side takes place in a counterclockwise direction, the angle formed is
a positive angle
If the rotation from the initial side to the terminal side is in a clockwise direction, the angle formed is
a negative angle
We can think of θ as being formed by rotating side OA about the vertex to side OB. In this case, we call side OA the
initial side
We can think of θ as being formed by rotating side OA about the vertex to side OB. In this case, we call side OB the
terminal side
The angle formed by rotating a ray through one complete revolution has a measure of
360 degrees
is 1/360 of a full rotation
1 degree
Angles that measure 90 degrees are called
right angles
angles that measure 180 degrees are called
straight angles
Angles that measure between 0 degrees and 90 degrees are called
acute angles
angles that measure between 90 degrees and 180 degrees are called
obtuse angles
Two angles with a sum of 180 degrees are called
supplementary angles
If two angles have a sum of 90 degrees, then they are called
complementary angles
Give the complement and the supplement of each angle.
1) 40 degrees
2) 110 degrees
3) θ
1) 50 degrees and 140 degrees
2) -20 degrees and 70 degrees
3) 90 degrees and 180 degrees
We denote the angles (or vertices) of a triangle with
uppercase letters
We denote the lengths of the sides of a triangle with
lowercase letters