9514 1404 393
Answer:
radius = 5 cm
Step-by-step explanation:
The point of "show your work" is to have to do exactly that. If you know the answer to the problem, you are being requested to show how you got it. If you got it by using a web calculator, then show your input and its result.
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If you worked the problem yourself, you probably did it by filling in numbers in the equation for the area of a circle:
A = πr²
78.5 = 3.14×r²
Dividing both sides by 3.14 gives the square of the radius:
78.4/3.14 = r² = 25
Taking the positive square root gives the radius:
r = √25 = 5
The area is in square centimeters, so the radius is in centimeters:
radius = 5 cm
Answer:
C) 2
Step-by-step explanation:
step 1: Find mean of data set
2+4+4+5+7+8 = 30
30/6 = 5
Mean = 5
step 2: subtract each data value from the mean and square it
5-2 = 3; 3² = 9
5-4 = 1; 1² = 1
5-4 = 1; 1² = 1
5-5 = 0; 0² = 0
5-7 = -2; (-2²) = 4
5-8 = -3; (-3²) = 9
Add the squared results:
9+1+1+0+4+9 = 24
Divide 24 by 6 to get the Variance of 4
Take the square root of the Variance to get the Standard Deviation
= 2
Answer: 150 boys
Step-by-step explanation:
Let the number of boys be x
Since there were 200 more girls than boys, the number of girls will be: = x + 200
Since the ratio of boys to girls was 3:7, this can be solved further below:
3/7 = x/x+200
Cross multiply
(7 × x) = 3(x + 200)
7x = 3x + 600
7x - 3x = 600
4x = 600
x = 600/4
x = 150
The number of boys enrolled is 150
Number of Girls will be:
= X + 200
= 150 + 200
= 350
Check: Number of boys / Number of girls
= 150/350
= 3/7
= 3:7
