True or false: the circumference of a semicircle is equal to 1 / 2 of the circle and then multiplied by the diameter Many students in my class say it's wrong, but I say it's right!

wrong
Circumference of semicircle = π R + 2R

The longer the circumference of a circle, the larger the area______ (judge right or wrong)

The perimeter of a circle is 2 π R, which is proportional to the radius. The larger the perimeter is, the larger the radius is, and the larger the area is

The area of two semicircles is the area of a whole circle

The area of two semicircles is the area of a whole circle
The area of a semicircle with two equal radii is the area of a whole circle
The circumference of a whole circle must be longer than that of a semicircle (wrong)
The circumference of a circle is related to its radius

RELATED INFORMATIONS

1. The longer the circumference of a circle, the larger the area of the circle?
2. The circumference of a circle is always Pai times the diameter
3. A ship can use up to 6 hours of diesel oil. When it goes out, it goes with the wind, 30 kilometers per hour. When it goes back, it goes against the wind, and the distance per hour is 45 times of that when it goes with the wind?
4. Type A alcohol contains 72% pure alcohol, and type B alcohol contains 62% pure alcohol. If each kind of alcohol is 15 liters more than the original, the pure alcohol content after mixing is 63.25%, how many liters of each kind of alcohol will be taken in the first mixing? After the first mixing, the pure alcohol content is 62%
5. The net income of Xiaoming's orchard in 2003 was 8000 yuan. If 4% of the net income was used to pay the tax on special agricultural and forestry products, and 2680 yuan was set aside for family expenses, the rest of the money would be deposited in the bank for five years. If the annual interest rate was 6.66%, how much of the principal and after tax interest could Xiaoming get when it was due? (5% of the interest tax)
6. Is the perimeter of the two figures the same in the following questions? Why
7. The area of a circle is 24 square meters. How to calculate the circumference of the circle
8. The perimeter ratio of the two circles is 4:5, and the area ratio of the two circles is 4:5______ ．
9. In a circle with a radius of 22 cm, cut a sector with a center angle of 144 degrees. The sector area is () square meters?
10. If the area of a sector is 5 / 11 of the area of its circle, what is the arc length of the sector?
11. How to calculate the perimeter area of a circle?
12. How to calculate the circumference and area of a circle
13. The sum of circumference, diameter and radius of a circle is 46.4cm. What is the circumference and area of the circle?
14. How to calculate the circumference and area of a circle It's better to use a simple method. You can also help to solve some problems Brother and sister, help
15. What is the circumference and area of a circle? Don't be too complicated. Come on
16. The area of a semicircle is 50.24. To find the circumference of the semicircle, we must have a complete formula, not just words and a few numbers,
17. Do two circles have the same perimeter and the same area?
18. If two circles have the same perimeter, they must have the same area______ (judge right or wrong)
19. The problem of the circumference of a circle is urgent 1. A 20 meter long rope is used to encircle a tree trunk for six times, leaving 1.16 meters. How many meters is the diameter of the tree trunk, 2. A yong road is 47.1 meters long. Xiao Ming rolls an iron ring on the Yong road. The diameter of the iron ring is 30 cm. How many turns does the iron ring have to turn when rolling from one end of the Yong road to the other The problem of Yonglu, the unit is different, the formula calculation, I just that, missed the word, now most need the second problem
20. A semicircular flowerbed, its radius is 5cm, its perimeter is how many meters?