LINES AND SEGMENTS

Definition of Line :

A line segment is a section of a line bounded by two points or connecting two points.

Types of lines :

Line segment :

A line segment is a collection of finite points which has a definite length. It has a start point and an endpoint. It is the shortest distance between two points that can be measured. 

Types of angles 

Problem 1 :

The ray opposite to KN is _____

Solution :

Opposite rays :

Two rays are opposite rays, by definition, if 

1) They have the same endpoint, and 

2) Their union is a line.

By observing the above diagram, 

The ray opposite to KN is KJ.

Problem 2 :

Another name for LM is _____

Solution :

By observing the above diagram, 

Another name for LM is LN.

Problem 3 :

The coordinate of L is _____

Solution :

By observing the above diagram, 

The coordinate of L is 3.

Problem 4 :

The length of LN is ____

Solution :

The length of LN is 4.

Problem 5 :

MJ = _____

Solution :

MJ = 9

Problem 6 :

A segment congruent to KM is _____

Solution :

By observing the previous question diagram, 

Congruent is same shape and same size.

So, a segment congruent to KM is LN.

Problem 7 :

The point on LM whose distance from L is 2 is _____

Solution :

By observing the previous question diagram, 

The point on LM whose distance from L is 2 is M.

Problem 8 :

The point on LK whose distance from L is 2 is _____

Solution :

By observing the previous question diagram, 

The distance between L and M is 2.

Refer to the diagram and classify each angle as acute, right, obtuse, or straight.

Problem 1 :

∠A ____

Solution :

By observing the diagram.

∠A is acute angle. (30^º)

Because, acute angle is greater than 0^º and less than 90^º is called acute angle.

Problem 2 :

∠ABC ____

Solution :

By observing the diagram.

∠ABC is obtuse angle.

∠ABC = 60 + 40

= 100 (more than 90)

Because, obtuse angle is greater than 90^º and less than 180^º is called obtuse angle.

Problem 3 :

∠BDC ____

Solution :

By observing the diagram.

∠BDC is right angle (90^º).

Because, right angle is 90^º.

Problem 4 :

∠ADC _____

Solution :

By observing the diagram.

∠ADC is straight angle (180^º).

Exactly 180^º is called straight angle.