Hi there!
We can use the following kinematic equation:
[tex]v_f^2 = v_i^2 + 2ad[/tex]
vi = initial velocity (6.7 m/s)
vf = final velocity (0 m/s at top of trajectory)
a = acceleration due to gravity (-9.8 m/s²)
d = max height reached (? m)
We can plug in the knowns:
[tex]0 = 6.7^2 + 2(-9.8)(d)\\\\[/tex]
Solve for 'd':
[tex]d = \frac{6.7^2}{2(9.8)} = \boxed{2.29 m}[/tex]
