base = 7 m
[tex]\begin{gathered} \text{area = 17.5 m}^2 \\ \text{area of triangle=}\frac{1}{2}bh \\ \text{where} \\ b=\text{base} \\ h=\text{height} \\ \text{area of triangle}=\frac{1}{2}\times7h \\ 17.5=\frac{7h}{2} \\ \text{cross multiply} \\ 35=7h \\ h=\frac{35}{7} \\ h=5\text{ m} \end{gathered}[/tex]height = 5 meters