19. Five marks exercise problem V

A trianglular shaped glass with vertices at $A(-5, -4)$, $(B(1,6)$ and $C(7,-4)$ has to be painted. If one can of paint covers $6 \ square \ feet$, how many cans of paint will be required to paint the whole glass, if only one coat of paint is applied?

 

Answer:

 

The cans required to paint the whole glass $=$ .