Two intersecting lines cannot be parallel to the same line is stated in the form of :

1) an axiom
2) a definition
3) a postulate
4) a proof

Euclid stated that if equals are subtracted from equals, the remainders are equals in the form of :

1) an axiom
2) a postulate
3) a definition
4) a proof

Two planes intersect each other to form a :

1) plane
2) point
3) straight line
4) angle

Euclid stated that all right angles are equal to each other in the form of :
1) an axiom
2) a definition
3) a postulate
4) a proof

Which of the following needs a proof ?

1) axiom
2) theorem
3) postulate
4) definition