A coin with a radius of 1cm rolls along the edge of the triangle cardboard. The three sides of the triangle are 6cm, 7cm and 8cm respectively. When the coin rolls back to its original position, what is the distance of the center of the coin

A coin with a radius of 1cm rolls along the edge of the triangle cardboard. The three sides of the triangle are 6cm, 7cm and 8cm respectively. When the coin rolls back to its original position, what is the distance of the center of the coin

The distance of the center of the coin = the length of the three sides of the triangle plus the circumference of the circle with radius 1 = 6 + 7 + 8 + 2 π = 21 + 6.28 = 27.28

How long does a coin with a radius of 1 cm roll 30 times

188.4 cm

Cut a 20 cm square cardboard into a rectangular paperboard with a volume of more than 550 cubic cm

Set the carton height as H
h(20-2h)^2>550
4h(h-10)^2>550
2h^3-40h^2+200h-275>0
two point three five

Rectangular paperboard, 90cm long and 60cm wide, cut into several squares of the same size without surplus
How many centimeters is the maximum side length of the cut square?
How many such squares can be cut out?

The maximum common divisor of 90 and 60 is 30, so the maximum side length of a square is 30 cm

How many pieces of paperboard can be cut into a square of the same size with 80 cm in length and 60 cm in width, and how much is the area of each piece?
Actually, I don't know who to choose,
Well, I'll choose the one who answers first

120 pieces, each with an area of 4 square centimeters

A rectangular cardboard, 90cm in length and 60cm in width. To cut it into several squares of the same size, there is no surplus. How many centimeters is the maximum side length of the square? How many such squares can be cut out?
List the formulas,

90=2×3×3×5；
60=2×2×3×5；
The greatest common divisor is 2 × 3 × 5 = 30 cm;
So the maximum side length is 30 cm;
Number = 90 △ 30 × 60 △ 30 = 6;
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Cut a 20 cm long and 16 cm wide rectangular paper into a square of the same size. There is no paper left. At least how many pieces can be cut? At most?
The length of the square is the whole centimeter

The factors of 20 are 1,2,4,5,10,20
The factors of 16 are 1,2,4,8,16
At least, the side length of a square is the greatest common factor of 20 and 16, which is 4cm and can be cut
(20 / 4) × (16 / 4) = 20
At most, the side length of a square is the least common factor of 20 and 16, which is 1 cm and can be cut
(20 / 1) × (16 / 1) = 320

A 35 cm long, 25 cm wide rectangular sheet iron, four corners were cut equal to the square, just folded into a 5 cm deep uncovered iron box, volume

The volume is 15 × 25 × 5 = 1875 cubic centimeters

In a 80 cm long, 50 cm wide rectangular iron sheet four corners cut a side length of 10 cm small square, and then make a no cover water tank
What's the volume of this tank?

60 × 30 × 10 = 18000 cm3 = 18 liters

A 30 cm long, 25 cm wide rectangular sheet iron, four corners of each cut side length of 5 cm square, make a 5 cm deep uncovered rectangular iron box
What's the volume of this iron box in cubic centimeter
If the height of a cuboid is reduced by 5cm, it will become a cube. At this time, the surface area will be reduced by 120cm. What is the volume of the cuboid?
Write down the steps and use Chinese characters for multiplication and division

Height: 5cm
Width: 25-5-5 = 15 (CM)
Length: 30-5-5 = 20 (CM)
Volume: 5 × 15 × 20 = 1500 (CM & amp; 178;)
2.120÷4=30（cm²）
30÷5＝6（cm）
6×6×11=396（cm²5