Euclid was a native of $\ldots \ldots \ldots .$

Give a definition for parallel lines. Are there other terms that need to be defined first? What are they,and how might you define them?

Solve the following question using an appropriate Euclid's axiom:
In the figure,$X$ and $Y$ are the mid-points of $AC$ and $BC$ respectively,and $AX = CY$. Show that $AC = BC$.

$A$ solid has.........

Euclid's second axiom is:

The things which are double of the same thing are