Question 334864
The area of a triangle is,
{{{A=(1/2)bh=(1/2)(h+6)h=140}}}
I'm assuming you meant 140 sq. cm. and not 140 sq. feet.
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{{{h^2+6h=280}}}
{{{h^2+6h-280=0}}}
{{{(h-14)(h+20)=0}}}
Only positive {{{h}}} results make sense here,
{{{h-14=0}}}
{{{h=14}}}cm
{{{b=14+6}}}
{{{b=20}}}cm