What does the word pythagorean mean?

Which of the following statements is not true? a.parallel lines are lines in the same plane that never intersect. b.congruent figures have the same shape and same size angles and sides. c.similar figures must have the same shape and the same size. d.a rotation is when you turn a figure around a certain point.

When you answer this can you explain

He mass of a single atom of carbon can be found by dividing the atomic mass (12.01 g) by 6.022 x 10^23. which is the mass of a single carbon atom, correctly written in scientific notation with the correct number of significant figures?