1, the base angle of the triangle is 45 degrees, and the top angle is (90) degrees. This triangle is called isosceles right triangle.

2. There is a 20-cm-long iron wire to enclose a quadrilateral with opposite sides of 4 cm. This quadrilateral can be a rectangle.

The hour hand of the clock is 3 cm long, and its tip has gone (6 cm) in one day and night.

4. On a rectangular iron plate with a length of 10 decimeter and a width of 6 decimeters, at most (15) circular iron plates with a diameter of 2 decimeters can be intercepted.

5. A small cube with a side length of 1 cm needs at least (4) cubes to make a larger cube, and (1000) cubes to make a larger cube with a side length of 1 decimeter. If these cubes are arranged in a row, they can be arranged in (10) meters.

6. 20% of a number is 100, and 3/5 of this number is (300).

7. There are 48 students in Class 6 (1) today, and two of them are on leave due to illness. The attendance rate on this day was (96 )%.

8. Team A and Team B complete a project in 20 days. It is known that the work efficiency ratio of Team A and Team B is 4: 5, and it takes Team A (45) days to complete the project alone.

9. If the quotient of a divided by b is 2, then a: b = (2):1.

10, 5/8 of a is equal to 5/ 12 of b, and A ∶ B is equal to (2)∶3.

1 1, add 2.5 to the former term of 4∶ 15, and add (9.375) to the latter term to keep the ratio unchanged.

12, the side length ratio of the two cubes is 1∶3, the surface area ratio of the two cubes is (1)∶9, and the volume ratio is (1)∶27.

13, 6/5 tons: 350kg, the simplified ratio is (24: 7), and the ratio is ().

14. After 1/8 of the number of people in Class A is transferred to Class B, the number of people in both classes is equal. It turns out that the ratio of Class A to Class B is (4: 3).

15. The distance traveled by Party A is 4/5 of that of Party B, the time spent by Party B is 4/5 of that of Party A, and the speed ratio between Party A and Party B is (16: 25).

16. It was judged to be disproportionate. If yes, indicate what proportion:

(1), when the concentration is constant, the amount of water and medicine. (proportional)

(2) The number of wheel revolutions is fixed, and the distance is related to the wheel circumference. (proportional)

(3) The cone has a certain volume and a high bottom radius. (out of proportion)

(4), 4x-5y = 0, (x, y is not equal to 0), x and Y. (proportional)

17. A number consists of five million tens, eight thousand and forty tens. This number is written as (5008400), rewritten as (50084) ten, and the mantissa after ten thousand is omitted as (50 1) ten. Round up or down

Between 18 and 50, only the number with prime factor 2 is ().

19. A rope is 4 meters long. Divided into five segments on average. Each section belongs to this rope (1/5), and its length is (0.8) m, which is equal to 1 m (4/5).

The unit of 20, 3/8 is (1/8), plus four such units, it is 87.5%.

2 1, with single-digit fraction in brackets, 3/4 < (7/9) < 4/5.

22. The least common multiple of15+5 is (3) times the greatest common divisor, and their direct greatest common divisor is () times, which is the (quotient) of these two numbers.

23, expressed in letters:

(1) Team A completed a project in one day and Team B completed another project in two days. The number of days completed by two teams.

( 1/(a+b))

(2) The quotient of 3 times the sum of A and 7 divided by 5. (3(a+7)/5)

(3) quotient of n divided by m (n/m)

24. A 2-meter-long wooden stick with a cross-sectional diameter of 6 cm increased its surface area (54 cubic centimeters) after being cut into four sections, and its original volume was (1800 cubic centimeters).

25, x=5b-2b B and x are in (positive) proportion.

26. The length of one rope is 6/7 of that of the other, and the other is longer than the other (1/7).

27. The approximate value of an integer in tens of thousands is 50000, the maximum value is (54999) and the minimum value is (45000).

28. A rectangular piece of paper with a length of 30 decimeters and a width of 20 decimeters can cut out at most (35) isosceles triangles with a right angle of 4 decimeters and guess at most (35) circles with a radius of 2 decimeters.

29. In a right triangle, the lengths of three sides are 6 cm, 8 cm and 10 cm respectively, and the area of this triangle is (24) square cm.

30. A cylindrical glass with an inner diameter of 10cm and a depth of 16cm accounts for 80% of the glass. If the medicine is filled, it should be (20) ml.

3 1. If a book is priced at 10 yuan, the net profit is 25%. If the net profit is 40%, each book is priced at (1 1.2) yuan.

Add 12 to the molecule of 32.4/1. To keep the size of the fraction unchanged, please add (33) to the denominator.