Use a 72 cm wire to make a cuboid frame, 8 cm long and 6 cm wide. How many cm high is it?

Use a 72 cm wire to make a cuboid frame, 8 cm long and 6 cm wide. How many cm high is it?

The sum of length, width and height is 72 △ 4 = 18 cm
Height: 18-8-6 = 4cm

A rectangular aluminum block with the length, width and height of 16 cm, 5 cm and 7.5 cm respectively is melted and cast into a cylinder with the diameter of 8 cm at the bottom, and the height of the cylinder is 10 cm
Keep two decimal places

V rectangle = 16 × 5 × 7.5 = 600 (cm3)
(8 △ 2) ^ 2 × 3.14 = 50.24 (square centimeter)
Height of cylinder: 600 △ 50.24 = 11.94 (CM)

There is a cylindrical iron block, 30 cm high and 8 cm in diameter at the bottom. It is melted into a cuboid of 3 cm long and 4 cm wide. How high is the cuboid

3.14 * (8 / 2) square * 30 = 1507.2cm3
1507.2/(3*4)=125.6cm
I'm in grade six. I've just learned

A classroom is 10 meters long and 7 meters wide. If it is paved with square bricks with a side length of 2 decimeters, how many pieces do it need?

2 decimeters = 0.2 meters
10x7 ÷ (0.2x0.2) = 1750 pieces
A total of 1750 tiles are needed
Thank you for your help

What are the 56 nationalities

Ethnic minorities 1. Mongolian is a long history and legendary nation, living a nomadic life of "moving by water and grass". Most of China's grasslands have left the footprints of Mongolian herdsmen, so it is known as the "proud son of Grassland". 2. Hui is a simple

Simplification (Sina + Sina / 2) / 1 + cosa + cosa / 2

Can you write the fraction more clearly? You can't distinguish the numerator and denominator at all!

The three sides of a right triangle are 3cm, 4cm and 5cm respectively. The height of the hypotenuse of the triangle is

The three sides of a right triangle are 3cm, 4cm and 5cm respectively
That is, the two right angles are 3cm and 4cm
So triangle area = 1 / 2 × 3 × 4 = 6 (CM & # 178;)
According to the area method, the height on the hypotenuse is 6 × 2 △ 5 = 2.4 (CM)

It is known that a ^ 1 / 2 + A ^ - 1 / 2 = 3
Find: A ^ 1 + A ^ - 1
a^2+a^-2

It's very simple
a^1/2+a^-1/2=3
Square both sides of the equation
a+2+a^-1=9
∴a^1+a^-1=9-2=7
Similarly, a ^ 1 + A ^ - 1 = 7 is squared
a^2+2+a^-2=49
∴a^2+a^-2=47

Solving inequality 3 (x-1) a

When a ＞ 0, the unequal sign of a is dropped on both sides, and the direction remains unchanged
Then 3x-3 < 2
Get x < 5 / 3
The inequality does not hold when a = 0
When a ＜ 0, the direction of the unequal sign is changed
Then 3x-3 > 2
X > 5 / 3
The answer is over

Draw the largest circle in a rectangle 12 cm long and 8 cm wide. The area of the circle is______ Square centimeter

2, = 3.14 × 16, = 50.24 (square centimeter); answer: the area of this circle is 50.24 square centimeter