The idea in brief. The new line passes through the given point and has the same direction as the given line. Copy the direction exactly and make the new line pass through the point. In the lesson. In the previous lesson, you used a ruler and a set square to draw perpendicular lines. Today, we will draw a line through a point, parallel to another line. The new line must go through the point. It keeps the same direction, so the two lines never meet.
Lesson video, with the working
Draw a parallel
3 min 37 s
The film teaches 3 questions in turn. Each question shows first; its working is written as the film explains it.
Question 1 of 7 · Basic · free to tryPaper construction. Use a ruler and set square to draw a line through D…Paper construction. Use a ruler…
Paper construction. Use a ruler and set square to draw a line through D parallel to AB. Mark the parallel lines with matching arrows. Compare your drawing with the model.
Work it out on paper, then open the working and check your answer against it.
Place a ruler against another edge of the set square and hold the ruler still.
Slide the set square along the ruler until the drawing edge passes through D.
Draw the line through D.
Mark the parallel lines with matching arrows.
Ans: A straight line through D, parallel to AB, with matching arrows on the two lines.
Answer: A straight line through D, parallel to AB, with matching arrows on the two lines.
For parents
What are the steps for drawing parallel lines with a set square in P3?
The last Primary 3 lines lesson uses the same tools in a different way.
What your child learns here
The last Primary 3 lines lesson uses the same tools in a different way. Your child draws a line through a marked point that is parallel to a given line, then marks the pair as parallel with matching arrows.
A parallel line keeps the same direction as the given line, so the two never meet.
One edge of the set square is lined up along the given line, and a ruler is placed against another edge.
Sliding the set square along the ruler keeps its direction while it moves to the point.
The new line passes through the point, and matching arrows show the pair is parallel.
Does the answer make sense?
The new line through the point must keep the same gap from the given line all along, even if it is shorter or longer than the given one. Your child can measure the gap near each end with a ruler held square to both lines; the two readings should match.
How to practise these questions
The Basic questions practise sliding the set square along the ruler to keep the direction. The Intermediate questions add slanted lines and points far from the given line, so the ruler must be held firmly while sliding. If a parallel drawing is stuck, watch the solution film for that question and try again later from Revision.
Questions parents ask
Why does drawing a parallel line need both a ruler and a set square? The set square holds the direction of the first line, and the ruler is a straight track for it to slide along. Sliding keeps the direction the same, so the new line comes out parallel.
Can my child draw parallel lines on squared paper without a set square? On squared paper, yes: a line that goes the same number of squares across and up as the first one is parallel to it. On plain paper, as in most questions here, the ruler and set square are needed.
What do the arrows on parallel lines mean? Matching arrows show that the lines are parallel. If a figure has two parallel pairs, the second pair is usually marked with double arrows to tell them apart.
