If the mass of a material is 50 grams and the volume of the material is 12 cm^3, what would the density of the material be?

The density of the material would be 
25/6 grams per cm^3.
to obtain the result above this is what we do:
density is calculated as: (the mass of the given material or object) / volume of the material 
which leads us to 50grams /12cm^3
 

Distance^2= yellow line ^2 (see picture) = 30^2 + 49^2so distance = squareroot of (300^2 +49^2)i dont know if this is how to solve it, but i cnt think of another way