Solution

Given that side of the square plot $$=m$$
Height and base of the triangular plot $$=m$$
Area of the square plot $$={m}^{2}$$
$$\therefore$$ Area of square $$={(side)}^{2}$$
Area of the triangular plot $$=\cfrac{1}{2}\times m\times m=\cfrac{1}{2}{m}^{2}$$
($$\because$$ Area of triangle $$=\cfrac{1}{2}\times base\times height$$)
Total area of the plot $$=$$ Area of the square plot + Area of the triangular plot
$$\Rightarrow$$ $${m}^{2}+\cfrac{1}{2}{m}^{2}=\cfrac{2{m}^{2}+{m}^{2}}{2}=\cfrac{3{m}^{2}}{2}$$