Tuesday, July 15, 2014

Given the equilateral triangle ABC and the isosceles triangle DBC, what is AB+DB if the perimeter of DBC is 50 and BC=24?

Consider the isosceles triangle DBC with BC = 24 and a
perimeter of 50.  Assuming 24 is the unique side of the triangle, you can write the
following equation:


CD + DB + BC =
50


CD + DB + 24 = 50


CD + DB +
24 = 50


CD + DB = 26


These
sides are equal because it is an isosceles triangle, so they each equal
13.


Therefore, DB = 13


Since
triangle ABC is equilateral and BC = 24, then AB = 24.


AB +
DB


24 + 13 =
37


Solution: 
37


**Note**


This
was assuming BC is the unique side of the isosceles triangle.  If BC is one of the
matching sides of the isosceles triangle, the answer
changes.


CD + DB + BC = 50


24
+ DB + 24 = 50


DB + 48 = 50


DB
= 2


AB + DB


24 + 2 =
26


Another possible answer is 26.

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