using proportions to solve these activites

[mexicomom]

A model train locomotive is approximately 194 mm long. How long was the actual locomotive if the model was made on the HO scale? (change your answer from mm to the nearest whole m.)

 

[HallsofIvy]

It helps a whole lot to know that HO scale is 1:87.1!

So you have
\(\displaystyle \frac{model}{real}= \frac{194 mm}{x}= \frac{1}{87.1}\)

(I presume that you understand that the real locomotive is larger than the model so the larger "87.1" corresponds to the real locomotive and the "1" to the model.)

So multiplying on both sides by 87.1x we have \(\displaystyle (87.1)(194 mm)= x\)
(That will give x in mm, of course. You will want to change to meters.)

 

[mexicomom]

A 1 over 25 (1/25) scale model sports car is 5.5 inches long. What was the length of the actual car to the nearest inch?

 

[MarkFL]

Before posting another problem (which should be done in another topic, but I noticed you did post the second problem in another topic as well), you should give feedback to the help you were given on the first problem (and good etiquette dictates that you might want to thank the person helping you as well ). Show how you would apply this help to solve the problem, and this gives us an idea of where you may need further help.

 

[HallsofIvy]

A 1 over 25 (1/25) scale model sports car is 5.5 inches long. What was the length of the actual car to the nearest inch?

If you did not learn anything from my first response, there is really no point in my responding to this!