Answer: True.
The ancient Greeks could bisect an angle using only a compass and straightedge.
Explanation:
The ancient Greek mathematician Euclid who is known as inventor of geometry.
The Greeks could not do arithmetic. They had only whole numbers. They do not have zero and negative numbers.
Thus, Euclid and the another Greeks had the problem of finding the position of an angle bisector.
This lead to the constructions using compass and straightedge. Therefore, the straightedge has no markings. It is definitely not a graduated-rule.
As a substitute for using arithmetic, Euclid and the Greeks learnt to solve the problems graphically by drawing shapes .