Answer:
3 feet
Step-by-step explanation:
The standard deviation of the frequency distribution is 5.54
<h3>How to determine standard deviation?</h3>
The table of values is given as:
x f(x)
0-3 13
4-7 13
8-11 10
12-15 11
16-19 0
20-23 3
Rewrite the table by calculating the class midpoints:
x f(x)
1.5 13
5.5 13
9.5 10
13.5 11
17.5 0
21.5 3
Start by calculating the mean using:

This gives

Evaluate

The standard deviation is then calculated as:

So, we have:

Evaluate

Solve

Hence, the standard deviation is 5.54
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Oldest = 2x
Middle = x + 5
Youngest = x
2x + x + 5 + x = 57
combine like terms
4x + 5 = 57
subtract 5 from both sides
4x = 52
divide both sides by 4 to isolate x
x = 13
Oldest = 2x = 2(13) = 26
Middle = x + 5 = 13 + 5 = 18
Youngest = x = 13
Answer:
x = 32
m∠7 = 94
m∠8 = 86
m∠3 = 94
Step-by-step explanation:
(2x + 30) + (3x - 10) = 180
5x + 20 = 180
5x = 160
x = 32
m∠7 = 2(32) + 30 = 94
m∠8 = 3(32) - 10 = 86
<u>or</u>
m∠8 = 180 - 94 = 86
<u>m∠3 ≈ m∠7</u> (corresponding angles)