Question 886198
{{{ A = (1/2)*h*( B + b ) }}}
Multiply both sides by {{{ 2 }}}
{{{ 2A = h*( B + b ) }}}
Divide both sides by {{{ h }}}
{{{ ( 2A ) / h = B + b }}}
Subtract {{{ B }}} from both sides
{{{ ( 2A ) / h - B = b }}}
And now you can write it in reverse order:
{{{ b = ( 2A ) / h - B }}}
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You can check it
Suppose
{{{ h = 4 }}}
{{{ B = 3 }}}
{{{ A = 8 }}}
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{{{ A = (1/2)*h*( B + b ) }}}
{{{ 8 = (1/2)*4*( 3 + b ) }}}
{{{ 2*8 = 5*( 3 + b ) }}}
{{{ 3 + b = ( 2*8 )/4 }}}
{{{ b = 16/4 - 3 }}}
{{{ b = 1 }}}
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And now:
{{{ b = ( 2A ) / h - B }}}
{{{ b = ( 2*8 ) / 4 - 3 }}}
{{{ b = 16/4 - 3 }}}
{{{ b = 4 - 3 }}}
{{{ b = 1 }}}
OK