Question 732174
You have to picture this triangle with the 3rd side being 
formed by the surface of a table and the 2.5 cm side and the
16.5 cm side above the table. The junction of the given sides
have a hinge between them so you can make any size triangle
you want with the 3rd side being the table's surface.
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Spread the hinged sides out so the given sides lay out flat
on the table. Now you have the limit of how long the 3rd
side can be- it is {{{ 2.5 + 16.5 = 19 }}} cm
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Now swing the 2.5 cm side back so it fold onto the 16.5 cm side
and lay it on the table. This tells you the short limit of the 3rd
side. It is {{{ 16.5 - 2.5 = 14 }}}
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So the 3rd side has to be between 19 and 14. It can't be 14
because that would be just a line. The answer is D. 17