Find distance using map measurements

  • Thread starter Thread starter dudxex
  • Start date Start date
  • Tags Tags
    Map Measurements
AI Thread Summary
The discussion focuses on calculating the actual distance between two cities based on a map scale of 1 inch to 80 miles. The calculation shows that if the cities are 2.75 inches apart on the map, the actual distance is 220 miles. Participants confirm the calculation and emphasize the importance of dimensional analysis to ensure accuracy. They also mention the need for proper unit conversions if different units are used. Overall, the method for determining distance using map measurements is validated through shared calculations and insights.
dudxex
Messages
1
Reaction score
0
Summary:: That is the problem down there.
The scale on a map is 1 inch (in.) ? 80 miles (mi). If two cities are 2 & 3/4in. apart on the map, what is the actual distance between the cities?

So what I did was convert the scales 80/1 mi per in. and multiplied it to 2 & 3/4in which I got an answer of 220 miles apart? somebody please check my answer? thanks a lot.
 
Physics news on Phys.org
Iffin 1 inch=80miles, wouldn't 2 inches = 160miles, and 2&3/4 inches = 160 + (3/4*80)?---160+60=220, maybe I misunderstood the question.
 
Please post homework questions and homework-like questions in our homework section (I moved the thread).

I agree with your answer.
 
  • Like
Likes jedishrfu
You could also have done it with decimal notation

80 km/inch * 2.75 inch = 220 km // notice dimensionally the inch units cancel leaving km as the answer's unit of measure. Dimensional checks are useful for checking an answer ie that you aren't missing some conversion factor.

As an example, if the problem said it was 80km/inch and you traveled 2.75 centimeters then you'd need to find the inches per centimeter factor (ie 0.3937 in/cm) to complete the calculation.

https://www.khanacademy.org/math/al...on/v/dimensional-analysis-units-algebraically
 
Since ##px^9+q## is the factor, then ##x^9=\frac{-q}{p}## will be one of the roots. Let ##f(x)=27x^{18}+bx^9+70##, then: $$27\left(\frac{-q}{p}\right)^2+b\left(\frac{-q}{p}\right)+70=0$$ $$b=27 \frac{q}{p}+70 \frac{p}{q}$$ $$b=\frac{27q^2+70p^2}{pq}$$ From this expression, it looks like there is no greatest value of ##b## because increasing the value of ##p## and ##q## will also increase the value of ##b##. How to find the greatest value of ##b##? Thanks
Back
Top