Calculate the mass percent of calcium,phosphorus,and oxygen in calcium phosphate $Ca_{3}(PO_{4})_{2}$.

First,calculate the molar mass of $Ca_{3}(PO_{4})_{2}$:
$= 3 \times 40 + 2 \times (31 + 4 \times 16) = 120 + 2 \times 95 = 310 \ g/mol$.
Mass percent of calcium $= \frac{3 \times 40}{310} \times 100 = \frac{120}{310} \times 100 = 38.71 \%$.
Mass percent of phosphorus $= \frac{2 \times 31}{310} \times 100 = \frac{62}{310} \times 100 = 20.00 \%$.
Mass percent of oxygen $= \frac{8 \times 16}{310} \times 100 = \frac{128}{310} \times 100 = 41.29 \%$.