The answer is 10 :) ........
Every confidence interval has associated z value. As confidence interval increases so do the z value associated with it.
The confidence interval can be calculated using following formula:

Where

is the mean value, z is the associated z value, s is the standard deviation and n is the number of samples.
We know that standard deviation is simply a square root of variance:

The confidence interval of 95% has associated z value of <span>1.960.
</span>Now we can calculate the confidence interval for our income:
Answer:
A. 112 m^2
Step-by-step explanation:
If the scale factor is 4, the area of the larger figure is 4^2 times that of the smaller one.
... (7 m^2)·4^2 = 112 m^2
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The scale factor for area is the square of the scale factor for linear dimensions. When we talk about a scale factor without qualification, we mean the scale factor for linear dimensions.