The height of a triangle is twice it's base and the area is 576 square inches . What is the length of the base?

First, we'll recall the formula of the area of a triangle,
that contains the base and the height.

A = b*h/2
(1)

b = base

h =
height

From enunciation, we have
that:

h = 2b (2)

We'll
substitute (2) in (1) and we'll get:

A =
b*2b/2

We'll simplify:

A =
b^2

From enunciation, the value of the area
is:

576 square inches =
b^2

We'll take square root both
sides:

sqrt 576 = sqrt b^2

b =
24 inches

The length of the base of triangle
is b = 24 inches long.