ella bought some key chains. if she paid 24$ for the key chains and each one cost the same wbole-dollar amount, how many could s
2 answers:
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Answer:
Interval [16.34 , 21.43]
Step-by-step explanation:
First step. <u>Calculate the mean</u>
Second step. <u>Calculate the standard deviation</u>
As the number of data is less than 30, we must use the t-table to find the interval of confidence.
We have 6 observations, our level of confidence DF is then 6-1=5 and we want our area A to be 80% (0.08).
We must then choose t = 1.476 (see attachment)
Now, we use the formula that gives us the end points of the required interval
where n is the number of observations.
The extremes of the interval are then, rounded to the nearest hundreth, 16.34 and 21.43
A pyramid is regular if its base is a regular polygon, that is a polygon with equal sides and angle measures.
(and the lateral edges of the pyramid are also equal to each other)
Thus a regular rectangular pyramid is a regular pyramid with a square base, of side length say x.
The lateral faces are equilateral triangles of side length x.
The lateral surface area is 72 cm^2, thus the area of one face is 72/4=36/2=18 cm^2.
now we need to find x. Consider the picture attached, showing one lateral face of the pyramid.
by the Pythagorean theorem:
thus,
thus:
(cm^2)
but
is exactly the base area, since the base is a square of sidelength = x cm.
So, the total surface area = base area + lateral area =
cm^2
Answer: cm^2
(and the lateral edges of the pyramid are also equal to each other)
Thus a regular rectangular pyramid is a regular pyramid with a square base, of side length say x.
The lateral faces are equilateral triangles of side length x.
The lateral surface area is 72 cm^2, thus the area of one face is 72/4=36/2=18 cm^2.
now we need to find x. Consider the picture attached, showing one lateral face of the pyramid.
by the Pythagorean theorem:
thus,
thus:
but
So, the total surface area = base area + lateral area =
Answer: