# A first look at Euclid's Elements

## Instructions

#### Warning: Allow the Graphics and Java Applets to fully load before clicking anywhere

*If you accidentally interupt the transmission before it is finished by clicking
somewhere, you must press the "Refresh" button to start all over again from the beginning*

Once you get to the main Page for Euclid's Elements follow the link called
"Using the Geometry Applet"
to get an idea how to move the objects and reset the diagram.

Next go to the
"Table of Contents"
to find a particular proposition to answer the following questions

## The Questions YOU need to answer

1. You already know a lot of theorems. Identify what theorem or postulate you
studied that go with the following propositions:

Book I, Prop 15

Book I, Prop 18

Book I, Prop 25

Book I, Prop 27

Book I, Prop 28

Book I, Prop 29

Book I, Prop 47
2. Go back to
Book I, prop 15, and move the red dot. What relationship stays the same?

3. Can you make a side of a triangle so large that it is bigger than the other two combined?
In your own words, justify your answer. Go to
Book I, prop 20 (or
prop 17) for ideas from Euclid).

4. What is a "rectilinear" angle? (go to
Book I, prop 23)

5. Book I proposition 46
outlines instructions for constructing a square. Write a list of instructions
so you can construct one with the same method with a compass and straight edge.

Click here if you have time

*Send me e-mail (cct@ktb.net)*