2.1

Question 1

Line Segment

Answer 1

Segment AB consists of the endpoints A and B and all the points on the line AB that lie between A and B.

Question 2

Ray

Answer 2

Ray AB consists of the initial point A and all the points on the line AB that lie on the same side of A as B lies.

Question 3

Opposite Rays

Answer 3

If C is between A and B then ray CA and ray CB are opposite rays.

Question 4

Collinear

Answer 4

Points, segments, or rays that lie on the same line are collinear.

Question 5

Angle

Answer 5

An angle consists of two different rays that have the same initial point. The rays are the sides of the angle and the initial point is the vertex of the angle

Question 6

Acute Angle

Answer 6

An angle whose measure is greater than 0 degrees but less than 90 degrees.

Question 7

Obtuse Angle

Answer 7

An angle with measure greater than 90 degrees but less than 180 degrees.

Question 8

Right Angle

Answer 8

An angle with a measure of 90 degrees.

Question 9

Straight Angle

Answer 9

An angle with a measure of 180 degrees.

Question 10

Interior of an Angle

Answer 10

Every nonstraight angle has an interior. A point D is in the interior of angle A if it is between points that lie on each side of the angle.

Question 11

Exterior of an Angle

Answer 11

Every nonstraight angle has an exterior. A point D is in the exterior of angle A if it is not in the interior or on the angle.

Question 12

Adjacent Angles

Answer 12

Two angles are adjacent if they share a common vertex and ray, but have no common interior points.