Question 893712
The larger similar rectangle has linear dimensions k times the smaller rectangle.



Small rectangle, 8 cm by w cm.
Area, {{{8w=40}}}



Larger rectangle, 8k cm by kw cm.
Area, {{{8k*kw}}};
but also is given that {{{kw=10}}}.



Find two equations with two unknowns!
{{{8w=40}}} and {{{kw=10}}}.
First one gives {{{w=40/8=5}}}.
Using this in the second equation gives {{{k*5=10}}} and therefore {{{k=2}}}.



Find the requested area for the larger rectangle.
{{{8k*10}}}
{{{8*2*10}}}
{{{highlight(160*cm^2)}}}