1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
inn [45]
3 years ago
6

A rectangle has area 64 cm^2. A straight line is to be drawn from one corner of the rectangle to the midpoint of one of the two

more distant sides. What is the minimum possible length of such a line

Mathematics
1 answer:
padilas [110]3 years ago
3 0

Answer:

The minimum possible length of such a line is 8 cm

Step-by-step explanation:

If we had a rectangle, we can name each side "a" and "b".

The area of the rectangle will be:

S=a\cdot b = 64

Note: This is the constraint of our optimiztion problem.

Applying the Pitagoras theorem, the line, as in the figure attached, will have a length of:

L=\sqrt{(a/2)^2+b^2}=\sqrt{a^2/4+b^2

We can replace "a" as a function of "b":

ab=64\\\\a=64/b

Then,

L=\sqrt{\frac{1}{4}(\frac{64}{b} )^2 +b^2}=\sqrt{\frac{1024}{b^2} +b^2

To calculate the minimum length, we derive and equal to zero:

dL/db=\frac{d}{db} [(\frac{1024}{b^2}+b^2)^{\frac{1}{2}}  ]\\\\dL/db=\frac{1}{2} (\frac{1024}{b^2}+b^2)^{(-\frac{1}{2})}\cdot \frac{d}{db} [\frac{1024}{b^2}+b^2]\\\\ dL/db=\frac{2b+1024\cdot(-2)\cdot b^{-3}}{2\sqrt{(\frac{1024}{b^2}+b^2)}} \\\\\\ dL/db=\frac{2b-2048\cdot b^{-3}}{2\sqrt{(\frac{1024}{b^2}+b^2)}}

dL/db=\frac{2b-2048\cdot b^{-3}}{2\sqrt{(\frac{1024}{b^2}+b^2)}}=0\\\\\\2b-2048b^{-3}=0\\\\2b=\frac{2048}{b^3}\\\\b^4=\frac{2048}{2}  =1024\\\\b=\sqrt[5]{1024}\approx5.66

Now, we know that one side is 5.66 cm.

Then, the other side should be:

a=64/b=64/5.66=11.31

The length of the line for this side dimensions will be:

L=\sqrt{\frac{1024}{b^2} +b^2}=\sqrt{\frac{1024}{5.66^2} +5.66^2}\\\\L=\sqrt{\frac{1024}{32} +32}=\sqrt{32+32}=\sqrt{64}=8

You might be interested in
Please someone help me
FrozenT [24]
4. No
'And I think you can draw the diagram;)
7 0
3 years ago
A square has 7.5 inches. What is the area ?
kvv77 [185]

Answer:

7.5^2

56.25

Step-by-step explanation:

6 0
3 years ago
Read 2 more answers
please i need help lol The amount of clay students used for their last art project is weighed. The line plot displays the amount
Schach [20]

Answer:

2  1/4

Step-by-step explanation:

We need to see how much clay they used if each person in that group used 3/4 clay. There are 4 people in the group.

=> 3/4 x 4 = 12/4 =    3

Now, we need to see how much clay they used if each person in that group used 1/4 clay. There are 3 people in the group

=> 1/4 x 3 =   3/4

Now, we need to see how much more clay was used.

=>3 - 3/4

=> 3/1 - 3/4

=> Take the LCM of the denominators and make the denominators equal.

=> 12/4 - 3/4

=> 9/4

They used 9/4 more clay.

Since there are no options with 9/4, we need to make this improper fraction into a proper fraction.

=> 9/4 = 2  1/4

They used 2  1/4 more clay.

3 0
2 years ago
Tammy Ray purchases 20 file cabinets for $986.99. What is<br> the price per cabinet?
RSB [31]

Answer:

<h2><u>49.34</u></h2>

Step-by-step explanation:

986.99/20=49.3485

Divide 986.99 by 20 which gets you 49.3485 then just around up the 10.

Hope this helps! Have a great day. Remember your amazing and you got this! Alycia <3

7 0
3 years ago
Read 2 more answers
What is the answers to these questions
Vsevolod [243]

Answer:

1. equation

2.equation

3.equation

4. expression

5.expression

6.equation

7.expression

8.equation

9.expression

anything with = is an equation, without is expression.

3 0
3 years ago
Other questions:
  • A cyclist rides her bike at a rate of 36 kilometers per hour. What is this rate in meters per second? How many meters will the c
    7·2 answers
  • There are 5 cyclists in a race. There will be a first-place, a second-place, and a third-place prize awarded. In how many differ
    11·1 answer
  • Is 14 a root of the equation 2x - 16 = - 44 ? Why or why not
    8·1 answer
  • Plz answer quickkkk help will give 5 star rate if answer is right nd will say thx
    8·2 answers
  • For a party, three solid cheese balls with diameters of 2 inches, 4 inches, and 6 inches, respectively, were combined to form a
    13·1 answer
  • Which measure is equivalent to 48 quarts?
    14·2 answers
  • If fx = 5x - what is the value of f(5)?
    8·1 answer
  • Pls heeelp i dont want to fail
    11·2 answers
  • Answer the questions to describe the transformations of figure ABCD.
    8·1 answer
  • Please help will give brainlest!!
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!