Mathematics · Class 8
Practical Geometry
Constructing quadrilaterals given sides, diagonals, and angles.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Class 8 constructions include quadrilaterals given various conditions, and revisiting bisectors and special angles — exam questions require neat labelled diagrams with arcs.
Constructing Quadrilaterals
- Given 4 sides and 1 diagonal
- Given 3 sides and 2 included angles
- Given 3 sides and 2 diagonals
Steps
Draw rough sketch first. Use compass for equal sides and arcs for angles. Label vertices clockwise.
Special Cases
- Rhombus: all sides equal — use compass with fixed radius
- Rectangle: right angles using perpendicular construction
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Example 1: Quadrilateral
Construct quadrilateral ABCD with AB=4cm, BC=5cm, CD=4.5cm, DA=3cm, AC=6cm.
- 1Draw AC=6cm
- 2Arcs from A and C with given side lengths
- 3Join intersection points B and D
Answer
Completed quadrilateral ABCD
Example 2: Rhombus
Construct rhombus with side 5 cm and one angle 60°.
- 1Draw base 5 cm
- 2Construct 60° at one end
- 3Mark equal sides 5 cm
- 4Complete parallelogram
Answer
Rhombus with all sides 5 cm
Key Points to Remember
- ✓ Rough sketch guides construction order
- ✓ Show construction arcs
- ✓ Verify measurements after construction
Exam Tips
- • Write given data before steps
- • Use pencil and ruler only unless compass specified
Practice MCQs — Practical Geometry
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
To construct rhombus, all sides must be: