Use a 20 cm long, 10 cm wide rectangular paper, roll into a cylinder. 2011-2-22 17:54 questioner: mop803 | browsing times: 250 When the height is 10 cm, what is the maximum perimeter of the bottom surface? When the height is 20cm, what is the maximum perimeter of the bottom surface?

Use a 20 cm long, 10 cm wide rectangular paper, roll into a cylinder. 2011-2-22 17:54 questioner: mop803 | browsing times: 250 When the height is 10 cm, what is the maximum perimeter of the bottom surface? When the height is 20cm, what is the maximum perimeter of the bottom surface?

10:20
20:10

When the height is 20cm, what is the maximum circumference of the bottom surface?

24cm

Cut the rectangular paper 20cm in length and 10cm in width into the largest circular paper. What is its circumference?

This is the largest circle with a diameter equal to the width of the rectangle
So its perimeter is 10 * 3.14 = 31.4cm

Use a piece of rectangular paper 20cm in length and 10cm in width to roll it into a cylinder. (1) when the height is 20cm, what is the maximum floor area in square centimeter? What is the maximum side area

When the height is 20cm, the perimeter of the bottom surface is 10cm, so the radius of the bottom surface can be calculated as 2 π r = 10cm  r = 5 / π
Base area = π R2 = π × (5 / π) 2 = 7.96 square centimeter
Side area = 10 × 20 = 200 square centimeter

What kind of plane figure will you get if you unfold the side of a cylinder with a height of 10cm and a circumference of 20cm?

Height = 10cm, length = 20 * 3.14 = 62.8cm
The plane figure is rectangular

A cylindrical iron block with a circumference of 15.7 cm and a height of 10 cm is fused into a cone. If the bottom area of the cone is 25 square cm, what is its height?

5 (CM), 3.14 × 2.52 × 10 × 3 / 25, = 3.14 × 6.25 × 10 × 3 / 25, = 588.75 / 25, = 23.55 (CM); a: the height of the cone is 23.55 cm

A cone, its bottom circumference is 18.84, its height is 10 cm, its bottom area is () square centimeter
It's a question to fill in the blanks

From the perimeter of the bottom surface is 18.84, the radius of the bottom surface can be obtained
r=18.84÷3.14÷2
=6÷2
=3（cm）
So the bottom area is 3.14 × 3 & # 178; = 28.26 (CM & # 178;)
This question is too high to use at all

A cylindrical iron block with bottom circumference of 15.7cm and height of 10cm is melted and cast into a cone with bottom area of 25cm. What is the height of the cone?

15.7 divided by 2 π to get the radius,
Multiply the two radii by π to get the base area
The area of the bottom multiplied by 10 is the volume of the cylinder
Divide the volume of the cylinder by the base area of the cone and multiply by 2
[10×（15.7÷2π）²π]÷25×2

A cylindrical iron block with a circumference of 18.74cm and a height of 10cm on the bottom surface is melted into a cone with a bottom area of 25cm square. How many cm is the height of the cone
Why

Bottom radius of cylindrical iron block = 18.74 △ 3.14 △ 2 = 3cm
The volume of iron block is 3.14 × 3 & # 178; × 10 = 282.6 cubic centimeter
Melt into a cone,
Cone volume = bottom area × height / 3
Its height is 282.6 × 3 △ 25 = 33.91 cm

The circumference of a rectangle is 32cm. If the length is reduced by 6cm, the rectangle will become a square. What is the area of the original rectangle?
Come on, I need it today

The perimeter is 32cm, now the length is reduced by 6cm. Notice that the rectangle has two lengths, so the perimeter is reduced by 12cm. So the perimeter of the rectangle after it becomes a square is 32-12 = 20cm, so the side length of the square is 20 / 4 = 5cm. Because the length is reduced from 6cm to 5cm, the original length is 5 + 6 = 11cm