Question 1203371
The description due to being without the needed picture, gives two possibilities.  
Either the semicircle is at the rectangle's length or at the rectangle's width.


Area is either

{{{20*12+(1/2)pi*(20/2)^2}}}
{{{highlight(240+50pi)}}}

Or

{{{20*12+(1/2)pi*(12/2)^2}}}
{{{highlight(240+18pi)}}}
.