## DCG Revision - Basic ConstructionsBasic Constructions are the foundation upon which many topics are built, in particular Solids in Contact. They can come up as a short question in their own right or they also can also come up as part of a long question.
Loci is most commonly used in Solids in Contact questions but can come up as a stand alone question in Section A too. Best of luck with your revision! |

## SYLLABUS LEARNING OUTCOMES(Leaving Certificate Design and Communication Graphics Syllabus, 2006)

## Key Constructions You Need to Know

- Bisect a line
- Bisect an angle
- Construct perpendiculars to lines
- Dividing a line into a given number of parts or a given ratio
- Construct a circumscribing and inscribing circle around and inside a triangle
- Find the centre of a circle given 4 points or 2 chords
- Construct a triangle given its base, top angle and altitude
- Construct a triangle given the top angle, length of 1 side and the base
- Construct a triangle given the perimeter and the ratio of its sides
- Construct a tangent to a circle from a point on the circle and a point outside the circle
- Construct an external and internal tangent between 2 unequal circles
- Construct external and internal tangent arcs to 2 circles

## THE KEY USES OF LOCI YOU NEED TO KNOW

- Construct a circle to touch a line and 2 given points
- Construct a circle to touch both arms of an angle and a given point
- Construct a circle to touch a given circle and 2 given points
- Construct a circle to touch 3 given circles
- Construct a circle to touch a line and 2 given circles

## Practice Textbook Questions (Anderson, 2007)

- P9 Q8
- P10 Q11
- P10 Q12
- P16 Q8
- P16 Q9
- P17 Q11
- P23 Q3
- P26 Q16
- P26 Q19

## Past Exam Paper Questions

- 2012 A-3
- 2016 A-4
- 2017 A-3

## References

Leaving Certificate Design and Communication Graphics Syllabus. (2006). Dublin: The Stationary Office, p.15.

Anderson, D. (2007).

Anderson, D. (2007).

*Graphics in Design and Communication 1*. Dublin: Gill & Macmillan, pp.9-26.