91
Drawing patterns with circles
Textbook: Part 3, lesson 91, pp. 70–71
GoalDraw flowers and patterns with a compass: the opening stays the same and each new centre lies on the circle.
New words
pattern · naqshornament · ornamentpoint of intersection · kesishish nuqtasipetal · gulbarg
Explanation
To draw a flower with a compass: 1) draw a circle; 2) keep the opening unchanged, put the needle on a point of the circle and draw a new circle; 3) use the point where the new circle crosses the first one as the next centre, and so on. Six such circles fit around the first one and make a flower with 6 petals. Patterns can be made of circles and straight lines and coloured as you like.
Worked examples
The compass is opened to 3 cm: the distance from the flower’s centre to each new centre is 3 cm = 30 mm.
One flower has 6 petals; 5 flowers have 6 × 5 = 30 petals.
Class activity
“Ornament workshop”: children draw their own compass flower, build a pattern by the rules and swap with a neighbour to work out how it was drawn.
Practice
1
A pattern has 8 flowers with 6 petals each. How many petals are there in total?
48
2
A compass was opened to 3 cm to draw a flower. How many millimetres is the second circle’s centre from the first centre?
30
3
In an ornament strip each flower takes 12 cm. If a row has 25 flowers, how many metres long is the strip?
3
4
A pattern has 4 rows of 9 flowers, each with 6 petals. How many petals are there in total?
216
5
One petal needs 15 cm² of cloth. How many cm² of cloth are needed for 5 flowers with 6 petals each?
450