Geometrical Constructions
Two instruments, no measuring. Constructions are exact in a way a protractor never is, and the arcs you leave behind are the proof.
What this lesson covers
Geometrical Constructions is a 9-part Class 7 Mathematics lesson. Each part makes one point and then hands over to the next, so it can be read in a sitting or picked up again at the part you stopped on. It defines the idea in plain words before using it, works through an example step by step, breaks the topic into its parts and compares them, shows where it is used outside the textbook, names the mistakes that cost marks in an exam, ends with a recap of what to remember.
How it begins
A construction is a drawing made with only a straight edge and a pair of compasses. No protractor, no measuring angles. That restriction is not there to make life hard. A protractor is read by eye and is accurate to maybe half a degree. Compasses do not measure anything. They guarantee that two lengths are equal, because the same opening drew both.
The 9 parts
- Straight edge and compasses only
- The perpendicular bisector
- The angle bisector
- Angles without a protractor
- What fixes a triangle
- Locus: the set of all possible points
- Where marks get lost
- What to remember
- Watch one worked through
Practise Geometrical Constructions
Everything on QuizByt for Class 7 Mathematics that goes with this lesson: read it first, then test yourself while it is fresh.
🧠 5 quizzes on Geometrical Constructions (2 easy, 2 medium, 1 hard)
Work up from easy to hard: the hard quiz asks the Class 7 exam-style questions on Geometrical Constructions.
🖨️ Printable worksheet
Geometrical Constructions on paper for Class 7, with room to write the working out. Preview the first page free.
🎮 Games for Class 7 Mathematics
Number and logic games at the right level for Class 7. Passing a quiz on Geometrical Constructions earns the credits that open them.
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