Question 946810

if rectangle {{{ABCD}}} is rotated {{{270}}}° counterclockwise around point {{{D}}} to form rectangle {{{EFGD}}}, dimensions of the {{{ABCD}}}  and {{{EFGD}}}

given {{{EF=9cm}}}
the length of {{{AB}}} and {{{DC}}} equal to {{{EF}}},so,
{{{AB=DC=9cm}}} 

if the perimeter of rectangle {{{ABCD}}} is {{{30cm}}}, then

{{{2AB+2BC=30cm}}}

{{{AB+BC=15cm}}}

{{{9cm+BC=15cm}}}

{{{BC=15cm-9cm}}}

{{{BC=6cm}}} => since {{{BC}}} equal to {{{ED}}} and {{{FG}}},we have

{{{ED=6cm}}} and {{{FG=6cm}}}

since segment {{{EC=ED+DC}}} and since {{{DC=9cm}}} and {{{ED=6cm}}}, we have

 {{{EC=6cm+9cm}}}

{{{EC=15cm}}}