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There are 56 students in a class. The number of boys is 8 more than that of girls. The ratio of male voice to female voice is (). What is the percentage of female voice in the class? There are 56 students in a class. There are 8 more boys than girls. What is the ratio of male voice to female voice? What is the percentage of female voice in the class?
13 to 10, 23 to 10
High school mathematics + simplification (2cos10 ° - sin20 °) / sin70 °
(2cos10°-sin20°)/sin70°
=(2cos10°-sin20°)/cos20°
=[cos10°+(cos10°-cos70°)]/cos20°
=[cos10°+2sin40°*sin30°]/cos20°
=[cos10°+2*1/2*sin40°]/cos20°
=[cos10°+cos50°]/cos20 °
=2cos30°*cos20°/cos20°
=2cos30°
=√ 3
answer:
(2cos10°-sin20°)/sin70°
=[2cos(30°-20°)-sin20°]/sin70°
=(2cos30°cos20°+2sin30°sin20°)/sin70°
=(2cos 30 ° cos20 °) / cos20 ° (induction formula sin70 ° = sin (90-20 °) = cos20 °)
=2cos30°
=2*（√3/2）
=√3
There are 56 students in class 5 (3), 32 boys and 32 girls. What's the proportion of girls in the class
Number of female students: 56-32 = 24
Female students: 24 / 56 = 3 / 7
The number of female students is 56-32 = 24
The proportion of female students in the class: 24 △ 56 = 3 / 7
(56-32)/56=3/7
Number of female students = 56-32 = 24
The percentage of female students in the class is: 24 / 56 = 3 / 7
That is, girls account for three seventh of the class
(56-32)/56x100%=3/7
A: Girls account for 3 / 7 of the class
Number of female students: 56-32 = 24
Female students: 24 / 56 = 3 / 7
The number of female students is 56-32 = 24
The proportion of female students in the class: 24 △ 56 = 3 / 7
Number of female students = 56-32 = 24
The percentage of female students in the class is: 24 / 56 = 3 / 7
That is, girls account for three seventh of the class
56-32)/56x100%=3/7
A: Girls account for 3 / 7 of the class
Number of female students: 56-32 = 24
Female students: 24 / 56 = 3 / 7
The number of female students is 56-32 = 24
The proportion of female students in the class: 24 △ 56 = 3 / 7
Number of female students = 56-32 = 24
The percentage of female students in the class is: 24 / 56 = 3 / 7
That is, girls account for three seventh of the class
56-32)/56x100%=3/7
A: Girls account for 3 / 7 of the class
Why is sin70 ° sin50 ° equal to cos20 ° cos40
70 ° and 20 ° are complementary
50 ° and 40 ° complement each other
So sin70 ° sin50 ° equals cos20 ° cos40
sin70=cos(90-70)=cos20
sin50=cos(90-50)=cos40
Multiply left and right
There are 46 students in class one, 21 girls and 25 boys. How many parts of the class are boys and girls?
21 out of 46 girls
25 out of 46 boys
What is cos20 degree
cos20＝0.93969262078590838405410927732473
zero point nine three nine six nine two six two zero seven eight five nine zero eight three eight
You can work it out with a slightly more advanced calculator
It is not a special value and can not be calculated by induction formula
I calculated by computer = 0.9396926607895...
There are 51 students in a class, including 21 girls. How many percent of the number of boys is that of girls
Male: 51-21 = 30
30 / 21 = 10 / 7 (10 / 7)
Do you want to analyze it?
How can sin70 ° be equal to cos20?
Induction formula
sin(π/2-x)=cos(x)
cos(π/2-x)=sin(x)
In triangle ABC, a = 70 °, B = 20 ° and C = 90 °
sin70°=sinA=BC：AB
cos20°=cosB=BC：AB=sin70°
In class 6 (1), there are 16 boys 1 / 3 and girls 1 / 4, 19 girls 1 / 3 and boys 1 / 4
Total number of class 6 (1)
A total of 60 people, including 12 boys and 48 girls
Then: 1 / 3x + 1 / 4Y = 16, 1 / 3Y + 1 / 4x = 19
Get
If you haven't learned the equation in primary school, calculate it like this: 16 + 19 = 35. This is the total number of 1 / 3 boys + 1 / 4 boys + 1 / 3 girls + 1 / 4 girls. That is the total number of 7 / 12 class. 35 times 12 / 7 is 60
A system of equations
Suppose that there are x boys and 4 girls
1\4X + 1\3 * 4（16-1\3X）= 19
The solution is x = 12
So there are 12 boys and 48 girls
What is cos20 degrees?
zero point nine three nine six nine
zero point nine three nine six nine
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