>>4681333There is a very thin slice missing in the middle whose surface area is equal to 1. This is because the 2 triangles cut from the top have a base of 8 units and a height of 3 units, while the two quadralateral polygons cut from the bottom have sides with triangles with a base of 5 units and a height of 2 units. By geometric principal, the corresponding angles of two such triangles added together to make the corner of a rectangle must be 90 degrees, since all 4 corners of any 4-sided figure is 90 degrees. The angles of the 3x8 triangle will be 20.56 deg., 69.44 deg., and 90 deg., while the angles of the 2x5 triangle will be 21.8 deg., 68.2 deg., and 90 deg. No combination of two associated angles will add up to exactly 90 degrees, though some will be close. The ones which are close to 90 degrees are used in this case. Specifically, they use the 68.2 and 20.56 degree angles, which sum up to 88.75 degrees. While close to 90 degrees, it is not the exact same, and will end up filling in the missing 1 square unit when accounted for.