Solution: Take the ground as the X axis and the intersection point between the left side of the gate and the ground as the origin, and establish a plane rectangular coordinate system.

The parabola passes through four points (0,0), (8,0), (1, 4), (7,4),

Let the analytical formula of this parabola be: y=ax2+bx+c,

∴ get the equations from the meaning of the question: c = 064a+8b+c = 0a+b+c = 4,

Solve the equation: a =? 47b=327c=0，

The analytical formula of this parabola is: y=-47x2+327x, and the vertex coordinate is (4647).

The height of the school gate is 647m ≈ 9.1m.