Answer:
8
Step-by-step explanation:
Using the Heron's formula we can find that the total area of the triangle is 84 inches.
Then, to find the height of the triangle, you have to multiply the area by 2 since the formula for the area of a triangle is (h*b)/2
Now, when we multiply 84 and 2 we get 168, so you have to divide 168 by 21 to find 8.
