Class 6 Maths · Original EZT practice
Lines and Angles (Class 6 Maths Chapter 2): the building blocks of geometry
Every shape in geometry starts with the same few ideas: a point, a line, a ray, and the angle formed when two rays meet. This chapter builds them one by one and ends with the skill you will use for years - measuring an angle with a protractor. Below: the ideas in plain words, then original EZT practice with worked answers. (Note: this is original practice, not a textbook exercise key.)
10 original worked examples, 10 fresh self-check questions, with explained answers. These are not copied textbook exercises, an official chapter index or a full answer key. No affiliation with NCERT is claimed.
Official sources for topic and edition context, checked 17 October 2026:
1. Points, line segments, rays and lines
A point marks an exact position - no size at all. A line segment joins two points and stops there (the edge of a ruler). A ray starts at one point and runs on forever in one direction (like a torch beam). A line runs on forever in both directions.
2. What an angle is
An angle forms when two rays share a starting point. That shared point is the vertex, and the two rays are the arms. We measure angles in degrees (°).
3. Types of angles
By size: acute (less than 90°), right (exactly 90° - a square corner), obtuse (between 90° and 180°), straight (exactly 180° - the arms make one line), reflex (more than 180° but less than 360°).
4. Measuring with a protractor
Place the protractor's centre on the vertex and its baseline along one arm. Read the scale that starts from 0° on that arm - the other arm points to the angle's size. Reading the wrong scale is the most common slip: an acute angle must give an answer under 90°.
5. Angles all around us
Corners of books and floor tiles are right angles; an opening door sweeps through every size from 0° to 90° and beyond; a triangle's three corners are three angles.
Choose, solve, check, then try a fresh question.
Before calculating, read the method prompt and name the condition that makes it useful. Write your own attempt. Open the steps only when you need them, and use the check to catch a wrong sign, unit or interpretation. Finish with the fresh question before reading its answer.
Classify a segment, ray and line
Choose the method: Count the endpoints and ask whether the figure stops or continues forever.
EZT practice question
Classify each: (a) the edge of a desk, (b) a sunbeam from the Sun to Earth, (c) a straight highway drawn going off the page both ways.
Show the worked solution
- The desk edge has two ends.
- The sunbeam starts at the Sun and travels onward.
- The highway drawing continues in both directions.
Answer: (a) line segment; (b) ray; (c) line.
Check: The endpoint counts are 2, 1 and 0 respectively.
Watch for this: A drawn line is still a model; its endpoints show which geometric object it represents.
Now try it yourself
What geometric object does the straight edge of a ruler model?
Check your answer
A line segment.
It has two endpoints and stops at both.
Count endpoints
Choose the method: A segment stops at both ends, a ray has one starting point, and a line has no endpoints.
EZT practice question
How many end-points does each have - a segment, a ray, a line?
Show the worked solution
- A segment stops twice.
- A ray starts once and continues.
- A line continues both ways.
Answer: Segment: 2; ray: 1; line: 0.
Check: Draw one of each and mark only the places where it stops or starts.
Watch for this: A ray is not a short line; it continues forever in one direction.
Now try it yourself
How many endpoints does segment AB have?
Check your answer
Two: A and B.
A segment stops at both named endpoints.
Read a three-letter angle name
Choose the method: In angle ABC, the middle letter is the vertex and the two outer letters point along the arms.
EZT practice question
In angle ABC (written angle-B), which point is the vertex and which are the arms?
Show the worked solution
- The middle letter B is shared by both rays.
- The rays run from B through A and from B through C.
Answer: Vertex B; arms BA and BC.
Check: The angle can also be named CBA because B remains in the middle.
Watch for this: The vertex is not always the first letter in the name.
Now try it yourself
In angle DEF, name the vertex and arms.
Check your answer
Vertex E; arms ED and EF.
The middle letter E is the shared starting point.
Name an angle from its rays
Choose the method: The shared starting point is the vertex; each ray from it is an arm.
EZT practice question
Two rays start from the same point P and pass through Q and R. Name the angle's vertex and arms.
Show the worked solution
- P is common to both rays.
- One ray passes through Q and the other through R.
Answer: Vertex P; arms PQ and PR.
Check: Both arms begin at P, not at Q or R.
Watch for this: A point an arm passes through is not the vertex unless both rays start there.
Now try it yourself
Two rays start at S and pass through T and U. Name the vertex and arms.
Check your answer
Vertex S; arms ST and SU.
S is the common starting point.
Classify angles by size
Choose the method: Compare the measure with 90°, 180° and 360°.
EZT practice question
Classify: 35°, 90°, 130°, 180°, 260°.
Show the worked solution
- 35° is less than 90°.
- 90° is a square corner.
- 130° is between 90° and 180°.
- 180° makes one straight line.
- 260° is between 180° and 360°.
Answer: 35° acute; 90° right; 130° obtuse; 180° straight; 260° reflex.
Check: Put each measure between the correct boundary values.
Watch for this: An obtuse angle is not every angle above 90°; it must also be below 180°.
Now try it yourself
Classify: 89°, 179°, 200°, 90°.
Check your answer
Acute, obtuse, reflex and right.
Compare each value with the type boundaries.
Read angles on a clock
Choose the method: Each hour step on a clock is 360° ÷ 12 = 30°.
EZT practice question
What angle do the clock hands make at exactly 3:00, and at 6:00?
Show the worked solution
- At 3:00 the hands are 3 hour-steps apart: 3 × 30° = 90°.
- At 6:00 they are 6 hour-steps apart: 6 × 30° = 180°.
Answer: 3:00 is a right angle, 90°; 6:00 is a straight angle, 180°.
Check: The 3:00 hands make a square corner and the 6:00 hands make one line.
Watch for this: Count hour steps, not the total minutes shown.
Now try it yourself
What angle do the clock hands make at exactly 9:00?
Check your answer
90°, a right angle.
The hands are 3 hour-steps apart, and 3 × 30° = 90°.
Choose the correct protractor scale
Choose the method: Start from 0° on the arm along the baseline, then sanity-check against acute or obtuse.
EZT practice question
You measure an angle and see 70° on one scale and 110° on the other. The angle is clearly smaller than a right angle. Which is correct?
Show the worked solution
- A smaller-than-right angle is acute.
- An acute angle measures less than 90°.
- Choose 70°, not 110°.
Answer: 70°.
Check: 70° and 110° add to 180°, the two readings on a protractor.
Watch for this: Reading the wrong scale can turn an acute angle into its supplement.
Now try it yourself
The scales show 60° and 120° for a clearly obtuse angle. Which is correct?
Check your answer
120°.
An obtuse angle is between 90° and 180°.
Measure and name an obtuse angle
Choose the method: Keep the centre on the vertex, the baseline on one arm, and read the scale beginning at 0°.
EZT practice question
One arm points to 0° on the inner scale; the other arm points to 120° on the same scale. What is the angle, and what type?
Show the worked solution
- Read 120° from the scale that starts at 0°.
- 120° lies between 90° and 180°.
Answer: 120°, obtuse.
Check: The angle is wider than a right angle but not a straight line.
Watch for this: Do not switch to the outer scale after choosing the inner 0°.
Now try it yourself
One arm is at 0° and the other at 80° on the same scale. Name the angle and type.
Check your answer
80°, acute.
80° is less than 90°.
Count angles and vertices in a triangle
Choose the method: Each vertex of a triangle holds one angle.
EZT practice question
How many angles does a triangle have, and how many vertices?
Show the worked solution
- A triangle has three corners.
- Each corner is a vertex with one angle.
Answer: Three angles and three vertices.
Check: One angle sits at each vertex.
Watch for this: Do not count the sides as angles; sides meet to form the angles.
Now try it yourself
How many angles and vertices does a quadrilateral have?
Check your answer
Four angles and four vertices.
It has four corners, one angle at each.
Turn through an angle
Choose the method: A full turn is 360°, so a quarter turn is 360° ÷ 4 = 90°.
EZT practice question
A door opens from shut to a quarter turn. What angle has it swept, and what type?
Show the worked solution
- A quarter of 360° is 90°.
- 90° is a right angle.
Answer: 90°, a right angle.
Check: The door edge moves from one wall direction to a perpendicular direction.
Watch for this: A quarter turn is not 45°; an eighth of a full turn is 45°.
Now try it yourself
What angle is swept in a half turn?
Check your answer
180°, a straight angle.
Half of 360° is 180°.
Try it yourself
Work these on paper before checking any notes. Answers are deliberately not shown here.
- Draw a point and a ray from it. How many different rays can start from one point?
- Classify: 89°, 179°, 200°, 90°.
- What angle do the clock hands make at 9:00?
- Measure any corner of your notebook and say what type of angle it is.
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Questions about this practice page
- What is the difference between a line, a ray and a line segment?
- A segment has two end-points, a ray has one and runs on forever in one direction, and a line has none and runs on forever both ways.
- What is an angle?
- The figure formed by two rays sharing one starting point (the vertex); its size is measured in degrees.
- What are the types of angles?
- Acute (under 90°), right (90°), obtuse (90°-180°), straight (180°) and reflex (over 180°, under 360°).
- How do I use a protractor correctly?
- Centre on the vertex, baseline along one arm, and read the scale that starts at 0° on that arm - sanity-check acute answers under 90° and obtuse answers above.
- Are these the NCERT Lines and Angles exercise questions?
- No. EZT pages are original practice on this chapter - use them to prepare for the textbook exercises, not as a substitute for your book.