Question 1001882
Two possible answers, so decide which one you want.


Dimensions are x and y for the rectangle.  Let the semicircle be connected to ONE of the lengths  for x.


Length of semicircle curved part is  {{{(1/2)2*pi*(x/2)=x*pi/2}}}.
Sum of the lengths of the three straight segments making the rest of the rectangle  is  {{{x+2y}}}.


Perimeter is {{{highlight(x+2y+(pi/2)x)}}}.