Boundaries of solids are:

$A$ surface is that which has $\ldots \ldots \ldots$ only.

State whether the following statement is True or False. Justify your answer.
Attempts to prove Euclid's fifth postulate using the other postulates and axioms led to the discovery of several other geometries.

State whether the following statement is True or False and justify your answer:
Euclid's fourth axiom states that things which coincide with one another are equal to one another.

How many dimensions does a solid have?

In the figure,if $\angle 1 = \angle 3$,$\angle 2 = \angle 4$ and $\angle 3 = \angle 4$,write the relation between $\angle 1$ and $\angle 2$,using an Euclid's axiom.