surface area and volume

These are all similar ...here is the first one...you try the other two

Surface area:

 

Three rectangular sides   12x8    + 12x12  +  11x12     in²

    plus two triangular   sides     area = 1/2 base * height         2   *     1/2 * 12x7.1    in²

 

Volume

triangular area    1/2 * 12x7.1 = 42.6

     volume = triangular area * 'depth' =   42.6 * 12   in³