# Introduction

This weeks topic is Skew Lines, defined below as:

"Two lines are called skew lines if they are neither parallel nor intersecting" (Anderson, 2014)

The constructions used in Skew Lines questions are are almost identical to Laminar Planes. For this reason it is a very good idea to think about Laminar Planes while trying to solve Skew Lines questions. Skew Lines can come up in Section A, Section B and they are also an important part of Geologic Geometry in Section C. Skew Lines is another one of those vital topics as chances are that it will appear somewhere on your Leaving Cert paper.

# SYLLABUS LEARNING OUTCOMES

(Leaving Certificate Design and Communication Graphics Syllabus, 2006)

## Descriptive Geometry of Lines and Planes

# What you need to know!

### Ordinary Level

Skew Lines is not part of the Ordinary Level Syllabus.

### Higher Level

- Find the shortest horizontal distance between two skew lines.
- Find the shortest perpendicular distance between two skew lines.
- Find the shortest distance between two skew lines at a given inclination to the horizontal plane.

# Practice Questions

## Practice Textbook Questions

(Anderson, 2014)

- P172 Q11
- P172 Q12

## Practice Exam Questions

### Short Questions

- 2015 A-4
- 2013 A-4
- 2011 A-3
- 2010 A-1

### Long Questions

- 2013 B-3
- 2012 B-3
- 2009 B-2

If you've been following my weekly revision guide you should now be feeling much more confident with your board drawing and you should also be starting to increase your speed. Revising early in the year is also a great way to keep your drawing skill up while doing the project. Best of luck with this week's questions and if you have any questions please leave them in the comments section below and I'll answer them as soon as I can.

### REFERENCES

Anderson, D. (2014). *Graphics in Design and Communication: One Volume Edition*. Dublin: Gill & Macmillan.

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