Question 1059552
The 4 sides of the rectangle, a, are:
{{{ x + x + y + y = 2x + 2y }}}
{{{ 2x + 2y = a }}}
{{{ 2*( x + y ) = a }}}
{{{ x + y = a/2 }}}
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The 4 sides of the square add up to:
{{{ z + z + z + z = 4z }}}
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If the piece of wood was {{{ 90 }}} cm long
then {{{ 4z = 90 - a }}}
{{{ z = ( 90 - a ) / 4 }}}
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Hope this helps