Surface area is just the area of all these 4 triangles plus the rectangle.
First we can find the area of the rectangle.

Half of the length is 28 cm, so the full length must be 28 * 2 = 56 cm.


The base for the left and right triangles are 27. The heights would be the net length minus half the length of the rectangle:

Calculate the area:



We have two of these triangles.

Now do the other two pair of triangles. The bases for them are 28 + 28 = 56 cm. The heights would be the net width minus the width of the rectangle:

Now find the area:



We have two of these triangles.

Add all the areas together:
The answer will be 6 x 5 x 4 / 3 x 2 x 1, 5 x 4 = 20. Hope this helps
Its 3l-40 or 5l-3 the answer is
It is close to 8. When you look for the square root of 59 you should get about 7.6811457... Round up and thats 8 round down that 7 but it should be 8.