Question

Which of the following statements is/are true?

• A. All right angles are equal to one another.
• B. Straight lines parallel to the same straight line are not parallel to one another.
• C. If equals are added to equals, the wholes are equal.
• D. A line segment can be extended on either side to form a straight line.

Answer 1

Answer: (A), (C), (D)

The correct options are
A All right angles are equal to one another.
C If equals are added to equals, the wholes are equal.
D A line segment can be extended on either side to form a straight line.

From Euclid's postulates, we have:

• A line segment can be extended on either side to form a straight line.
• All right angles are equal to one another.

From Euclid's axioms, we know that if equals are added to equals, the wholes are equal.

Also, from Proclus' postulate, we know that straight lines parallel to the same straight line are parallel to one another.