Construction of Trapezium

Objectives

Construction of a trapezium accurately for the given measurements.

• Estimated Time: 40 minutes.
• Materials/ Resources needed: a ruler, pencil, compass, and a blank piece of paper
• Prerequisites/Instructions, if any

1. Knowledge about using a compass and drawing perpendicular lines.

• Multimedia resources
• Website interactives/ links/ / Geogebra Applets

This has been taken from the website ; http://www.k6-geometric-shapes.com/trapezoid.html

• Process:

1. This construction can be made if the height of the trapezium along with the length of the four sides is known.
2. Draw a straight line lightly using your ruler and pencil on your paper. - This is what is called a construction line, and will be the base of the trapezium.
3. Indicate the two end points of the base of the shape with two points, measured by ruler.

Note:We know that the top and base line of a trapezium are parallel, and, we know the distance between them (the height).

4. Using compass, construct two lines (lightly) perpendicular to the base. On both of these lines measure the height of the trapezium, and indicate with two points (one on each perpendicular) Connect these two points using a light construction line. The second side of the trapezium will be 'somewhere' on this line.

5. Using ruler, measure the length of the third and fourth sides between these two paralell lines, using the points on the first construction line, as one end of the line segment. Mark with a point.

Note: You will now have four construction lines, intersecting at four vertices.

6. The required trapezium is the shape contained between the four points of intersection of these four lines.

7. Using a heavier line connect the four points to finish your shape.

• Developmental Questions:

1. Name the given parameters of a trapezium.
2. What would be the base ?
3. What are the measures of its 2 parallel sides ?
4. What is the measure of its height ?
5. How would you start the construction process ?
6. what is the method to draw perpendicular lines ?
7. How do you mark the height of the trapezium ?

• Evaluation:

The teacher can check the students constructions to evaluate.

• Question Corner:

1. Can you construct a trapezium when only its area is known ? Discuss.