Question 1048261
The walls are of uniform thickness.
Let {{{ x }}} = the thickness of the walls
If I subtract {{{ 2x }}} from each dimesion
of the exterior walls, I will have the
dimensions of the interior walls, so I can say:
{{{ ( 12 - 2x )*( 17 - 2x )= 176 }}}
{{{ 204 - 34x - 24x + 4x^2 = 176 }}}
{{{ 4x^2 - 58x + 28 = 0 }}}
{{{ 2x^2 - 29x + 14 = 0 }}}
Use quadratic formula
{{{ x = ( -b +- sqrt( b^2 - 4*a*c )) / (2*a) }}} 
{{{ a = 2 }}}
{{{ b = -29 }}}
{{{ c = 14 }}}
{{{ x = ( -(-29) +- sqrt( (-29)^2 - 4*2*14 )) / (2*2) }}} 
{{{ x = ( 29 +- sqrt( 841 - 112 )) / 4 }}} 
{{{ x = ( 29 +- sqrt( 729 )) / 4 }}} 
{{{ x = ( 29 - 27 )/4 }}}
{{{ x = 1/2 }}}
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The other possibility is:
{{{ x = ( 29 + 27 )/4 }}}
{{{ x = 56/4 }}}
{{{ x = 14 }}}  ( this is impossible, since one wall is 12' long )
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The wall is 6 inches thick ( 1/2 ft )
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check:
{{{ ( 12 - 2x )*( 17 - 2x )= 176 }}}
{{{ ( 12 - 2*.5 )*( 17 - 2*.5 )= 176 }}}
{{{ ( 12 - 1 )*( 17 - 1 ) = 176 }}}
{{{ 11*16 = 176 }}}
{{{ 176 = 176 }}}
OK