If you want to go the measuring route, you might try this.
Step 1
Controller: Measure the length of the <
top line> and of the <
bottom line>. Measure the distance between the two, this will become the <
center line>.
Image: Make a horizontal line the length of <
bottom line>. Make a vertical line the length of <
center line>. Move <
center line> so that it's bottom end point meets the center point of <
bottom> line.
Make a horizontal line the length of <
top line>. Move <
top line> so that the center point of <
top line> meets the top end point of <
center line>.

Step 2
Controller: Measure the length of <
top line 2>. Measure the distance between <
top line> and <
top line 2>, this will become <
center line top>.
Image: Make a vertical line the length of <
center line top>. Move <
center line top> so it's top end point meets the center point of <
top line>.
Make a horizontal line the length of <
top line 2>. Move <
top line 2> so that the center of <
top line 2> meets the bottom end point of <
center line top>.

Step 3
Controller: Measure the length of <
bottom line 2>. Measure the distance between <
bottom line> and <
bottom line 2>, this will become <
center line bottom>.
Image: Make a vertical line the length of <
center line bottom>. Move <
center line bottom> so it's bottom end point meets the center point of <
bottom line>.
Make a horizontal line the length of <
bottom line 2>. Move <
bottom line 2> so that the center of <
bottom line 2> meets the top end point of <
center line bottom>.

Step 4
Image: Connect the end points of the lines to get your shape.

Step 5
Image: Remove the inner lines.