What is the formula for area of a circle? 100 points
2 answers:
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The length (L) of the rectangle can be written as a function of the width (W)
:
Now since we know Area = Width*Length, we can write the area as a function of the width:
Distributing the W inside the parentheses we have:
We know the area is 54 ft^2, so we can rewrite it as:
Now solve for W by factoring (or by applying the quadratic formula):
Factor out a common 2W from the first two terms and a 9 from the last two terms:
Regroup the terms to get our fully factored equation:
This gives us the roots W = 6 and W = -9/2, but width can't be negative so we have width = 6 ft. Then remember that the length L = 2W - 3, so our length is:
So now we know that our rectangle is 9 feet long and 6 feet wide.
Now since we know Area = Width*Length, we can write the area as a function of the width:
Distributing the W inside the parentheses we have:
We know the area is 54 ft^2, so we can rewrite it as:
Now solve for W by factoring (or by applying the quadratic formula):
Factor out a common 2W from the first two terms and a 9 from the last two terms:
Regroup the terms to get our fully factored equation:
This gives us the roots W = 6 and W = -9/2, but width can't be negative so we have width = 6 ft. Then remember that the length L = 2W - 3, so our length is:
So now we know that our rectangle is 9 feet long and 6 feet wide.
Answer:
atleast 385
Step-by-step explanation:
Given that an electrical power company is looking to expand into a new market. Before they commit to supplying the new area with electricity, they would like know the mean daily power usage for homes there.
Population std deviation =
Sample size =
STd error of sample mean =
Margin of error for 95% would be Critical value ( std error)
Here since population std dev is known we can use Z critical value= 1.96
Sample size should be atleast 385