Find out how many centimeters the minute hand has moved is the circumference of this circle:
3. 14x 10x2-62.8cm。
How many square centimeters is the area of the circle swept by the minute hand?
3. 14x 10x 10 = 3 14c m2
2. How many square centimeters of paper do you need to cut 28.26 square centimeters of round paper?
This is the diameter of the circle:
28.26 divided by 3. 14=9
Because the square of 3 is 9, the radius of the circle is 3 cm.
3X2=6 cm
You need a square piece of paper with a side length of 6 cm.
3. There are 60% people in the Qupu group and 45% people in the Qufeng group, and there are three people in both groups. How many people are there in this class?
3 divided by (60%+45%- 1)
=3 divided by 0.05
=60 people
4. A section of road, two-seventh of the first day of construction, 40 meters more than the first day the next day, 300 meters in the first two days, to achieve the full length.
300-40 = 260m
260 divided by (2/7+2/7)
=455 meters
5. Boys are 40% of girls, more than girls 12, so I ask for boys.
Is this the right question? 40% of boys are girls, which means there are fewer boys than girls, and then there are more girls 12, which is contradictory.
6. After a batch of books is distributed to one fifth of the sixth grade, the rest are distributed to the third, fourth and fifth grades according to 3: 4: 5, and the fifth grade is divided into 40 books. How many books are there in this batch?
40 divided by 5=8 books
8X(3+4+5)=96 copies.
96 divided by (1-1/5) =120 copies.
7. A canal was completed two fifths in the first week, eleven kilometers in the second week, leaving only two sevenths. Find the length of the canal.
1 1/35 divided by (1-2/5-2/7)
= 1 1/35 divided by 1 1/35.
= 1 km