Euclid stated that all right angles are equal to each other in the form of

Which country did Thales belong to?

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 $AC = BC$.

One dimension in each step in the sequence of solids $-$ surfaces $-$ lines $-$ points is........ going on.

Read the following statements which are taken as axioms:
$(i)$ If a transversal intersects two parallel lines,then corresponding angles are not necessarily equal.
$(ii)$ If a transversal intersects two parallel lines,then alternate interior angles are equal.
Is this system of axioms consistent? Justify your answer.

$A$ line is a length without $\ldots \ldots \ldots$