Schooling · Class 6 · Mathematics · Playing with Constructions · Chapter on a page
CBSE Class 6 · Mathematics · NCERT Ganita Prakash
Playing with Constructions: chapter on a page
A cut of Shishya's notes for this chapter: the first paragraph of the introduction and the key ideas, formulas and facts, common mistakes and quick revision lists, word for word. Nothing is added or reworded; the worked examples are left out (they are on the chapter page).
About the notes: Written by Shishya's AI on 26 Sept 2026 from the chapter's title and class level, in Shishya's own words — not a copy or summary of the textbook. Read the official chapter for the book's own text, activities and exercises.
Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain.
Mind map
Drawn from the same notes by a fixed rule (no AI): each label is the item's own words — its bold term, its label before a colon, a short formula as written, or its first words.
The mind map as a list
- Key ideas
- A compass draws circles and arcs by…
- The radius is the distance from the…
- A line segment is a straight line…
- An arc is a part of a circle, like a…
- To construct a triangle, you need…
- Every construction has clear steps…
- Marks and labels (like A, B, C) help…
- Formulas and facts
- Radius
- Diameter
- Arc
- Line segment
- To copy a line segment
- Triangle rule
- Watch out for
- Changing the compass opening while…
- Not placing the compass point…
- Drawing rough circles by moving the…
- Forgetting to label points
- Measuring the radius but setting the…
What this chapter is about
This chapter teaches you how to draw shapes carefully using simple tools like a ruler (scale) and a compass. A compass is a tool with two arms — one has a sharp point, and the other holds a pencil. You use it to draw circles and arcs.
Key ideas
- A compass draws circles and arcs by keeping one point fixed and moving the pencil arm around it.
- The radius is the distance from the centre of a circle to any point on the circle. All radii of the same circle are equal.
- A line segment is a straight line with two end points. You can copy a line segment using a ruler and compass.
- An arc is a part of a circle, like a curved piece cut from a bangle.
- To construct a triangle, you need three measurements — these could be the lengths of all three sides.
- Every construction has clear steps that must be followed in order.
- Marks and labels (like A, B, C) help you keep track of points during construction.
Formulas and facts to remember
- Radius: The distance from the centre to any point on a circle.
- Diameter: The distance across a circle through its centre. Diameter = 2 × radius.
- Arc: A part of the boundary of a circle.
- Line segment: A straight path between two fixed points.
- To copy a line segment: Open the compass to match the segment's length, then draw an arc from a new point.
- Triangle rule: A triangle has three sides. One way to construct it is from the length of each side.
Common mistakes
- Changing the compass opening while drawing an arc → Hold the compass firmly and do not press too hard.
- Not placing the compass point exactly on the marked point → Always check that the sharp point sits right on the dot.
- Drawing rough circles by moving the compass too fast → Rotate slowly and steadily for a neat circle.
- Forgetting to label points → Always write the letters (A, B, C) so you know which point is which.
- Measuring the radius but setting the compass to the diameter → Remember, radius is half the diameter.
Quick revision
- A compass and ruler let you construct shapes accurately.
- Radius is centre to edge; diameter is edge to edge through the centre.
- To copy a segment, match the compass opening to its length.
- For a triangle, draw one side first, then use arcs to find the third point.
- Label every point clearly during construction.
- Take your time — neat work beats fast work.