lets convert the fractions first:
85 1/3 = 255/3 + 1/3 = 256/3
10 2/3 = 30/3 + 2/3 = 32/3
now, the equation to find the area of a triangle is:
area = heightbase/2
so the height is:
height = 2area/base
then we substitute:
height = 2(256/3)/(32/3)
= (2256/3)/(32/3)
= (512/3)/(32/3)
now, dividing by a fraction is the same as multiplying by that fraction upside down:
= (512/3)(3/32)
= (5123)/(332)
= 1536/96
= 16
therefore the height of the triangle is 16 ft