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torisob [31]
3 years ago
10

Radiation​ machines, used to treat​ tumors, produce an intensity of radiation that varies inversely as the square of the distanc

e from the machine. At 3​ meters, the radiation intensity is 62.5 milliroentgens per hour. What is the intensity at a distance of 2.7 ​meters?The intensity is______milliroentgens per hour. (Round to the nearest tenth as needed.)
Mathematics
1 answer:
iren [92.7K]3 years ago
4 0

Answer:

77.2 milliroentgens per hour

Step-by-step explanation:

The first step is to find the constant of proportionality

I ∝ 1/d²

I = k/d²

62.5 = k/(3)²

k = 562.5

The second step is to calculate the intensity at 2.7 meters:

I = 562.5/d²

I = 562.5/(2.7)²

I = 77.2 milliroentgens per hour

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Find four fractions between 1/10 and 1/8
Alex17521 [72]

9514 1404 393

Answer:

  5/48, 5/46, 5/44, 5/42

Step-by-step explanation:

We can choose unit fractions with denominators between 8 and 10, separated by (10-8)/5 = 0.4 units:

  1/8.4 = 5/42

  1/8.8 = 5/44

  1/9.2 = 5/46

  1/9.6 = 5/48

__

<em>Check</em>

  • 1/8 = 0.125
  • 5/42 ≈ 0.119
  • 5/44 ≈ 0.114
  • 5/46 ≈ 0.109
  • 5/48 ≈ 0.104
  • 1/10 = 0.100

_____

<em>Additional comment</em>

There are an infinite number of such fractions. We are given unit fractions with different denominators, so it works reasonably well to choose denominators between those given. Then the trick is to convert the fraction to a ratio of integers. In this case, multiplying by (5/5) does the trick.

__

Another approach is to write the fractions with a common denominator, then choose numerators between the ones given. For example, 1/10 = 4/40, and 1/8 = 5/40, so you could write some fractions with numerators between 4 and 5. Possibilities are 4.1/40 = 41/400, 4.3/40 = 43/400, 4.7/40 = 47/400, 4.9/40 = 49/400.

6 0
3 years ago
Help !!!<br>See question in image.<br>Please show workings .<br>​
ivolga24 [154]

Answer:

see explanation

Step-by-step explanation:

Given f(x) then the derivative f'(x) is

f'(x) = lim(h tends to 0 ) \frac{f(x+h)-f(x)}{h}

      = lim ( h to 0 ) \frac{4(x+h)^2-2-(4x^2-2)}{h}

      = lim ( h to 0 ) \frac{4(x+h)^2-2-4x^2+2}{h}

      = lim( h to 0 ) \frac{4x^2+8hx+4h^2-4x^2}{h}

      = lim( h to 0 ) \frac{8hx+4h^2}{h}

      = lim ( h to 0 ) \frac{4h(2x+h)}{h} ← cancel h on numerator/ denominator

      = lim ( h to 0 )  4(2x + h) ← let h go to zero

f'(x) = 8x

5 0
3 years ago
Two different lines lie in the same plane.
nikitadnepr [17]

Answer:

Two lines, both in the same plane, that never intersect are called parallel lines. Parallel lines remain the same distance apart at all times. The symbol // is used to denote parallel lines.

how to prove that two lines are equal: If two lines are cut by a transversal and the alternate exterior angles are equal, then the two lines are parallel. Angles can be equal or congruent; you can replace the word "equal" in both theorems with "congruent" without affecting the theorem. So if ∠B and ∠L are equal (or congruent), the lines are parallel.                                 therefore the answer is E. The two lines are everywhere equidistant.

8 0
2 years ago
Read 2 more answers
WHOEVER ANSWERS THIS QUESTION IN 5 MINS WELL GET THE BRAINLIEST ANSWER!!!! Ms. Kitts works at a music store. Last week she sold
lianna [129]
60 because she sold a total of 110
8 0
3 years ago
987÷z=164.5
AveGali [126]

Answer:

z=6

Step-by-step explanation:

987/z=164.5

multiply both sides by z

4 0
3 years ago
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