Question 1022022
If the length of the rectangle is {{{ L }}}
and the width is {{{ W }}}, then the formula
for circumference, {{{ C }}}, is:
{{{ C = 2L + 2W }}}
given:
{{{ L = 3W }}}
By substitution:
{{{ C = 2*3W + 2W }}}
{{{ C = 6W + 2W }}}
{{{ C = 8W }}}
{{{ 80 = 8W }}} cm
{{{ W = 10 }}}
--------------
{{{ L = 3W }}}
{{{ L = 30 }}}
--------------
Let {{{ A }}} = area
{{{ A = L*W }}}
{{{ A = 30*10 }}}
{{{ A = 300 }}}
The area is 300 cm2
-------------------
check:
{{{ C = 2L + 2W }}}
{{{ C = 2*30 + 2*10 }}}
{{{ C = 60 + 20 }}}
{{{ C = 80 }}} cm
OK