# Construction and loci

**This list supports the following learning objectives:**

use straight edge and compasses to construct:

• the midpoint and perpendicular bisector of a line segment

• the bisector of an angle

• the perpendicular from a point to a line

• the perpendicular from a point on a line

• a triangle, given three sides (SSS)

find simple loci, both by reasoning and by using ICT, to produce shapes and paths, e.g. an equilateral **triangle**

### Seaside

This video resource from Teachers TV is filmed at the seaside and raises questions on: construction of a triangle, similar triangles, scale drawing and loci.

A question is posed for each topic, offering a pause point for teachers to hold a freeze frame on screen while students discuss the question. The video is designed for teachers to use with an interactive whiteboard.

### Drawing

This resource contains two packs of SMILE cards containing a number of drawing activities including some requiring students to construct using a ruler, pencil and compass including triangles, angle bisectors, perpendicular bisectors, and drawing Islamic designs.

### Locus Mystery

I always try to make constructions serve a purpose. To solve this mystery students have to construct right angles, parallel lines and a perpendicular bisector of a line.

### Constructions

It is always usefiul to put the mathematics being carried out into some context.

This resource from Defence Dynamics looks at the military’s use of constructions.

Students are asked to draw constructions to represent how the military target hostile forces, stressing the importance of accuracy in calculations which consider projected paths. They will need to be able to construct scale drawings, an angle bisector, a perpendicular bisector, a triangle and a variety of loci.

### Constructions and Loci

I like, from the activity file, the constructing a running track activity. It requires students to think about how they go about constructing the drawing, needs accurate use of a pair of compasses and is set in a context with which most students are familiar.

### Drawing a rocket

A problem in which students have to use their skill constructing triangles in order to construct a picture of a space rocket.

This kind of activity is easily extended by asking students to draw a picture of their choice given certain criteria e.g. your picture must contain at least one equilateral triangle, one parallelogram, one square and an isosclels triangle.

### Shape, Space and Measures 2

Unit 5 Construction page 41 of the book, page 47 in the pdf)

covers:

A Building sites

B Constructing triangles

C Paralel lines

D Flying high

E Estimation through scale drawing

F Polypatterns