It's a isosceles triangle
For any triangle
[tex]\\ \tt\longmapsto cos\theta=\dfrac{Base}{Hypotenuse}[/tex]
[tex]\\ \tt\longmapsto cos30=\dfrac{6}{H}[/tex]
[tex]\\ \tt\longmapsto H=\dfrac{6}{cos30}[/tex]
[tex]\\ \tt\longmapsto H=\dfrac{6}{0.86}[/tex]
[tex]\\ \tt\longmapsto H=6.9\approx 7ft[/tex]
