Question 258353
The vertices are at (0,10), (10,10),(5,5) and (0,5)
You need to find the area of the rectangle (0,10) (10,5) (0,5) and (5,5)

the lengths are 5, 5,5,5
 so the area is 25
and the right triangle (10,5) ,(5,5) and (10,10) the right angle is at (10,5)
the two legs are length 5 and 5
area  1/2* 25
so together they are 25 +12.5=37.5 square units