The statement which is true is the airplane reaches its maximum height of 81 feet in 12 seconds.
Since the height of the plane is a function given by a parabola, we need to know the equation of a parabola in vertex form
The equation of a parabola with vertex (h,k) is given by y = a(x - h) + k
Since the height (in feet) of the airplane as a function of time (in seconds after the timer was started) is given by the equation h(t) = −(t − 12) + 81
So, the statement which is true is the airplane reaches its maximum height of 81 feet in 12 seconds.
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