For the two sides, do find the area by doing 2((base x height) / 2)so..
2.5 x 6 = 15m^2
The base is simply a rectangle so 6 x 10 = 60m^2
The top is 6.5 x 10 = 65m^2
The back is 2.5 x 10 = 25m^2
Add all of these up together to get
15 + 60 + 65 + 25 = 165m^2
Hope this helps! Any questions let me know :)