Where is the Store?

by

Angie, Beth, & Teisha


Problem: Three towns in Ireland, Poole, Bray, and Alton, are located 8, 3, and 5 miles, repectively, from a store. How far apart are the towns from one another if they are located at the vertices of an equilateral triangle?
Is the store inside, on, or outside the traingle?




First we can connect the vertices of the equilateral triangle that the towns form. From there we can constuct circles with radii of 3 and 5 at Bray and Alton, respectively. The unit mile was chosen at random. Whichever unit you decide to use as the mile, the ratios should always remain the same.


We can then see that where the two circles intersect are three miles and five miles away from Bray and Alton respectively. Now we can consider if either or those points are 8mi away from Poole. We can look at the above picture and elliminate point G because it is too close to Poole. With G elliminated, we can then consider point E. Upon measurement we find that the measure of line AE is 7.95cm.



This construction was done using computer software and the measurements are accurate. Unfortunately, it is difficult to get lines to be the exact length that you want them. Because of these minute differences in measurement to lengths appear to be slightly off the mark.
This construction shows the point E to be 3 miles from Bray, 5 miles from Alton, and 8 miles from Poole. With this restriction met, we can measure the length between the cities and get 6.5 miles.
With the construction done here the store is outside the triangle. I did try several constructions that might have the store inside or on the triangle, but I was unsuccessful. That of course does not make it proof that there are not solutions that exist for those situations, it simply means I am not yet smart enough to find them!!


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