Using three given sides of the triangle a, b, c, find its area by the Heron's formula

    area = ,


where s =  =  = 11 is the semi-perimeter.


So, the area is

    area =  =  = .


Another formula for the area of the triangle is

    area = ,  

where h is the altitude drawn to the sides AB.


It gives you an equation

     =  

or

    3*h = .


From this equation,  h =  = 6.99206  (rounded).    ANSWER