I.
[tex]a = 6 \ m\\h = 2,5 \ m\\\\P = \frac{1}{2}ah\\\\P = \frac{1}{2}\cdot6 \ m\cdot 2,5 \ m\\\\\boxed{P = 7,5 \ m^{2}}[/tex]
II.
[tex]a = 2,5 \ m\\h = 6 \ m\\\\P = \frac{1}{2}ah\\\\P = \frac{1}{2}\cdot2,5 \ m\cdot6 \ m\\\\\boxed{P = 7,5 \ m^{2}}[/tex]