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>
Answer:
11 m and 14 m
Step-by-step explanation:
Legs: x and y
---
1/2xy= 77 ⇒ xy= 154
√x²+y²= √317 ⇒ x²+y²=317
x²+y²+2xy= (x+y)²= 2*154+317= 625 ⇒ x+y= √625= 25
x= 25-y
xy=154 ⇒ y(25-y)= 154 ⇒ 25y- y²=154 ⇒ y²- 25y +154=0 ⇒ y=11 and y=14
x= 25-y= 14 and 11
Using the midpoint concept, it is found that the value of a is of a = 2.
<h3>What are the coordinates of the points?</h3>
Researching this problem on a search engine, the coordinates are given as follows:
<h3>What is the midpoint concept?</h3>
The midpoint between two points is the halfway point between them, and is found using the mean of the coordinates.
Hence the following system of equations can be built:
(b + 1 + 2a)/2 = 3.
b + 1 + 2a = 6.
b = 5 - 2a.
(a + 2 + 3b + 3)/2 = 5
a + 3b + 5 = 10
a + 3b = 5.
Since b = 5 - 2a, we have that:
a + 15 - 6a = 5.
5a = 10
a = 10/5
a = 2.
The value of a is of a = 2.
More can be learned about the mid-point concept at brainly.com/question/10956693
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Answer:
You didn't tell us much on what to do, so I just guessed you wanted it simplified. If you want a different answer, please do so tell me and I'll edit my answer to fit.
Simplified: 10
+ 
- 9
19 quantities of item A and 6 of item B were sold, respectively
<h3>How to determine the quantity sold</h3><h3>The missing information in the question are</h3>
- The cost of item A is $4 and
- The cost of item B is $2.
Using the information and the given parameters, we have the following system of equations:
A + B = 25
4A + 2B = 88
Multiply the first equation by 2
2A + 2B = 50
Subtract this equation from the second equation to eliminate B
2A = 38
Divide both sides by 2
A = 19
Substitute A = 19 in A + B = 25
19 + B = 25
Subtract 19 from both sides
B = 6
Hence, 19 quantities of item A and 6 of item B were sold, respectively
Read more about system of equations at:
brainly.com/question/14196682
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