Very urgent! The distance between two parallel lines is equal everywhere. 2. Two parallel lines either intersect or parallel. Are these two sentences correct? Please state the reasons Two parallel lines should be two straight lines

Very urgent! The distance between two parallel lines is equal everywhere. 2. Two parallel lines either intersect or parallel. Are these two sentences correct? Please state the reasons Two parallel lines should be two straight lines

1. The distance between two parallel lines is equal everywhere
Judgment: the concept of theorem
2. Two straight lines are either intersecting or parallel
Judgment: wrong
The premise is: to be in the same plane, then two lines either intersect or parallel
If they are not in the same plane, the two lines may not intersect or be parallel. For example, one of the 12 edges of a box does not intersect or parallel with a certain height. You might as well try

Mathematics problems of grade six in primary school A two meter long cylinder is cut into two sections, and the surface area increases by 12.56. The volume of this steel section is a kind-hearted help

The surface area increases by 12.56, so its bottom area is 12.56 divided by 2 = 6.28, and the volume is 6.28 times 2 = 12.56

A math problem of grade 6 in primary school A circle is a quarter of its size and is surrounded by a square. The area of the square is 5 square meters?

Because the side length of the square is the radius of the circle, so the area of the square is RXR = 5, and the area of the circle is 3.14xrxr, i.e. 3.14x5 = 15.7m2

Urgent need The base and height of a triangle are a meter and H meter respectively. If the base is increased by 5 meters and the height remains unchanged, it will become a new triangle with a base of (a + 5) cm. How many square meters is the area of this new triangle increased?

（a+5）×h÷2－a×h÷2
=5h/2
Area increased by 5h / 2 square centimeter

Math problem (Grade 5) The minuend is 40 more than the minus and 35 more than the difference —— （ ）

The difference between the subtraction and the subtraction is 40, so the subtraction is 40 + 35 = 75, and the subtraction is 35

A rectangular iron plate, 30 cm long and 25 cm wide. Cut the square with 5 cm side length from the four corners as shown in the figure, and then make it into a box. How many milliliters does this box have?

Because the length of the box is 30-5 × 2 = 20 (CM), the width is 25-5 × 2 = 15 (CM), and the height is 5cm,
So the volume of the box is:
20×15×5，
=300×5，
=1500 (cubic centimeter),
=1500 (ML);
A: the volume of this box is 1500 ml

Pole height / shadow length = what?

Rod height / shadow length = constant

A fraction A / b (both a and B are natural numbers) is known as 1

First of all, find out the fraction that conforms to the meaning of the question: 2 / 5, 2 / 6, 2 / 7; the fraction that conforms to the meaning of the question is a total of these three fractions; and then we will sum up: 1. What fraction may this fraction be? 2 / 5, 2 / 6, 2 / 72, which fraction can be converted into a finite decimal? 2 / 5 can be converted into a finite decimal (denominator is only a reduction of 5, which is the simplest fraction

1. Xiaoming has some sticks that are centimeter long. He took two of them, 4cm and 6cm long Please help him choose another one to make a triangle. What's the longest and the shortest 2. There is a parallelogram at the bottom of the wheat field, which is 250 high and 92cm high. The total yield of wheat is 16.1t. How many hectares are there in this wheat field, and how many tons of wheat are harvested per hectare 3. If the side length of a square increases by 10 cm, the area will increase by 1300 square centimeters. What is the original area of the square 4. There is a trapezoid bottom which is four times as high as the top bottom, which is 12cm high. If the bottom is reduced by 11cm and the upper bottom is increased by 7cm, it will become a rectangle. Find out the trapezoid area express thanks on one's knees

The longest is 9, and the shortest is 3, because the sum of the two sides is larger than the third side 250 * 92 = 231000 = 0.00023 ha 16.1/0.00023 = 70000 tons (unit is cm, doubt the wrong number) 1300 / 10 = 130 (130 + 10) / 2 = 70 70 70-10 = 60 60 * 60 = 3600 (11 + 7) / (4-1) = 66 * 4 = 24 (6 + 2

1. A log with a cross-section circumference of 12.56 decimeter is cut into five sections, and the surface area is increased by () square decimeter. 2. A rectangle is a cm in length and B cm in width. The height of the three-dimensional figure is () cm and the bottom product is () square centimeter by rotating one circle with the side length a as the axis 3. Pour some water into a cylindrical glass cylinder with a diameter of 2 decimeters on its bottom, completely submerge a cylindrical iron can with a bottom radius of 3cm and a height of 2cm. If the tin can is taken out of the cylinder, how many centimeters will the water level in the cylinder drop? 4. A 3-meter-long cylindrical wood is sawn into four cylindrical logs of the same length. The surface area is 471 square centimeters more than the original. What is the volume of this cylindrical wood? 5. Three cylinders of the same size are assembled into a large cylinder with a height of 30 cm, and the surface area is reduced by 40 square centimeters. The volume of each small cylinder is () cubic centimeter. A piece of rectangular paper with a length of 8 cm and a width of 6 cm is rolled into a cylinder (the joint is ignored), The side area of the cylinder is () square centimeter. A cylinder. The diameter of its bottom surface is 10 cm. If the height is increased by 2 cm, the side area will increase by (0 Pinggang cm)

1.(1)3.14*2²*8=100.48 (2)a (3)b²π
3.2dm=20cm
V iron pot = 3? * 3.14 = 28.26cm
V glass cylinder (before drawing) = 10? * 3.14 * 2 = 628cm
V glass cylinder (after pumping) = 628-28.26 = 599.74cm
The height (after pumping) was 599.74 ^ (10 ^ * 3.14) = 1.91cm
So: 20-1.91 = 0.09cm
4. Because 4 pieces were cut off, 6 sides were added
S base area = 471 △ 6 = 78.5cm2
3m=300cm
V ball = 78.5 * 300 = 23550cm
5.（1）100 （2）48 （3）62.8 （4）6.28 （5）78.5%