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Zina [86]
3 years ago
5

There are 2,100 bacteria in a circular petri dish. The dish has a radius of 40 millimeters. What is the approximate population d

ensity? (Use 3.14 for π)
Mathematics
2 answers:
pochemuha3 years ago
6 0
A petri dish is simply a circle; thus, we use the formula of the area of the circle which is <span>πr^2. 
Given r = 40 mm
A = </span>π(40)^2 = <span>5026.55 sq. mm
</span>
Population density = bacteria count / area
PD = 2,100 / <span>5026.55
PD = </span><span>0.417782 bacteria / mm sq.

Therefore, the answer is approximately 0.418 </span><span>bacteria per square millimeter.</span>
saul85 [17]3 years ago
3 0
Determine the area of the circular petri dish through the equation, A = <span>πr^2. Substituting the radius to the equation and solving for area gives, 5024 mm^2. The population density is obtained by dividing the population with the calculated area. Thus, the population density is approximately 0.418 bacteria per mm^2. </span>
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How can you determine if you need to use a combination or permutation to count the number of outcomes? Which will usually have m
Nadya [2.5K]

Answer with Step-by-step explanation:

Permutation : It is an arrangement of r elements out of n elements.

Combination : it is a selection of r element out of n elements .

Suppose we have a set

S={1,2,3}

If two elements are taken at a time then

Using permutation formula

Total number of outcomes=3P_2

Total number of outcomes=\frac{3!}{(3-2)!}

Total number of outcomes=3!=3\times 2\times1=6

Using combination formula

\binom{n}{r}=\frac{n!}{r!(n-r)!}

Total number of outcomes=\binom{3}{2}=\frac{3!}{2!1!}

Total number of outcomes=\frac{3\times2!}{2!}

Hence, total number of outcomes=3

Total number of outcomes determined by permutation have more outcomes.

Because permutation is an arrangement of elements  therefore, it consider order of arrangement of element   but combination is a selection of elements it does no consider order of elements

Arrangements of two elements out of 3 elements

{1,2},{2,3},{2,1},{3,2},{1,3},{3,1}

By using combination if two elements taken at a time then combination

{1,2},{2,3},{1,3}

4 0
3 years ago
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sweet-ann [11.9K]

Answer:

Dilations produce similar figures because the image and pre-image will have congruent corresponding angles. The corresponding side lengths of the figures will be proportional based on the scale factor. The shape is preserved and the sides are enlarged or reduced by the scale factor

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6 0
2 years ago
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barxatty [35]
(2/3)(1/4)=
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Elodia [21]

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Step-by-step explanation:

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3 0
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