Calculation formula of cuboid surface area: cuboid surface area = length * width *2+ width * height *2+ length * height *2, or cuboid surface area = (length * width+width * height+length * height) *2.
Because the two opposite faces are equal in area, count the back two faces first, then the front and back, and finally the left and right faces. If the length, width and height of a cuboid are A, B and C respectively, the surface area is S = (ab+bc+ca)×2, which is also equal to 2ab+2bc+2ca, 2(ab+bc+ca).
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Precautions:
1. A cuboid is a right prism with a rectangular base. Each rectangle of a cuboid is called a cuboid face, the line where the face intersects the face is called an edge of the cuboid, and the point where the three edges intersect is called the vertex of the cuboid.
2. The key to solve this problem is that the billet has changed from a cube to a cuboid steel, and the shape has changed, but the volume has never changed. So the volume can be obtained by the side length of the cube, and the unknown can be obtained by the volume of the cuboid = the bottom area × the height.
3, a cuboid block, from top to bottom, from left to right, from front to back, each chisel a square hole with a side length of 2 cm, through its center, and find the volume of the block after chisel. ? Length times width times height, minus 2x2x width, minus 2x2x height +2x2x2.
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