Question

Can anyone help?? I don't understand.

Answer 1

If the height and base are equal, that simply means that b = h, or h = b

and we know the area is 18 m²

$\bf \textit{area of a triangle}\\\\ A=\cfrac{1}{2}bh\qquad \begin{cases} b=h\\ A=18 \end{cases}\implies 18=\cfrac{1}{2}\cdot h\cdot h\implies 18=\cfrac{h^2}{2} \\\\\\ 36=h^2\implies \sqrt{36}=h$