How to calculate the combined surface area of two boxes

When combined, the surface area of the 2 contact surfaces is reduced.

The larger the area of the contact surface, the more surface area is reduced.

The maximum contact surface is: 15*10 =150

Therefore, the reduced surface area is: 2*150=300

The surface area of the original 1 cuboid is: 15*8*2+15*10*2+8*10*2= 700

Therefore, the percentage reduction is: 300 (700*2)=

The sum of the original surface area of the two cuboids is (8*10+8*15+10*15)*2*2=1400, and the minimum surface area after the merger is to combine the side with the largest area, that is, the 10*15 side, so the surface area of the new cuboid after the merger is (8*10+8*15)*2*2=800,800 1400=, that is, the minimum is the original.

The surface area is reduced by a maximum of 15 * 10 * 2 = 300 square centimeters.

The original surface area is (15*8+15*10+8*10)*4=1360 square centimeters.

300 1360 is approximately equal to, that is, approximately one percent less.

The surface area of two boxes of the same size.

The surface area is reduced by up to 2*15*10=300

The surface area is reduced at most.

Summary. The first type: kiss if the way of merging is like this.

The first type: kiss if the way of merging is like this.

Let its length, width and height be ABC

Then this is (ab+bc+ac) 4-ac, and the second case is.

Surface area = (ab+bc+ac) 4-bc

The third scenario is:

Surface area = (ab + bc + ac) 4-2ab

Kiss The front is all minus twice as much, I wrote it wrong.

To sum up, the three types are 1, (ab+bc+ac) 4-2ac2, (ab+bc+ac) 4-2bc3, (ab+bc+ac) 4-2ab

The calculation method of the mega file surface area of a cuboid with all sides of a rectangular face: cuboid surface area = (length and width + height + width of the long group) 2

The surface area of each face is rectangular and the two faces are square: rectangular branch surface area = length and width 4 + width and height 2

Or you can use the first one: box surface area = (length and width + length height + width) 2

The surface area of the two cuboids should be removed from the two faces that coincide and contact, and the surface area of the two cuboids is 140 + 48 = 188

There are 3 cases of coincidence, and there is no diagram.

In fact, the main point is the surface area of the two cuboids, and subtracting twice the area of the overlapping part is the surface area of the piece.

There are 3 floors of the traffic police command platform at Nanhu intersection, each with a height of 20cm and a diameter of 120cm, 100cm and 80cm respectively. Calculate how much area of this traffic police command platform is exposed?

It depends on how it is put together, or what it is put together.

Analysis: The two cubes merge into a single cuboid, that is, one side of each of the two cubes is docked together, so that the area of the two sides is lost.

Solution: Let the side length of the cube be a

Surface area of the box = (a x 6) x2 -2a = 12a -2a = 10a

If the cube side length is a, the combined surface area is 10a squared.

for the original total surface area of 5 to 6

(7*9+9*1+7*1)*2=79 square centimeters, 5*square centimeters.

79+ square centimeters.

Volume: 5 2= cm.

Cubic centimetre. 7*9*1=63 cubic centimeters.

157 + 63 = 220 cubic centimeters.

The surface area of a cuboid with all sides rectangular is calculated: the surface area of the cuboid = (length and width + length height + width) 2

The surface area of the cuboid is rectangular and the 2 faces are square: the surface area of the cuboid = length and width 4 + width and height 2

Or you can use the first one: box surface area = (length and width + length height + width) 2

Answer: The surface area of each cuboid cube edge length edge length 4 or The surface of each cuboid body is bright and the surface of the cube is known to collapse the surface area of the cube 2 3 Analysis: Compared with the cube, the area of 2 faces of each cuboid remains unchanged, and the area of 4 faces is only half of the original, that is, less.

The area of 2 faces, so the surface area of each cuboid is 4 times the area of one face of the cube, or the surface area of the cube.

(4, 6) two-thirds.

The surface area of the rectangular body a is only filed:(

The apparent area of the cuboid b is ((