Does anybody know what 26 divided by 648

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?

Which of the following parabolas opens down?

Which of the following represents the length of a diagonal of this trapezoid?