Answer:
Step-by-step explanation:
The perimeter of ABCD is 30cm
The Sum of the perimeter of three rectangles at the corner is 20cm.
following the variables as the same as you assigned
large rectangle: u by v
rectangle center A: 2a by 2b
rectangle center B: 2c by 2d
rectangle center D: 2e by 2f
2 equations (from the givens):
2u+2v=30
2(a + b + c + d + e + f )= 20
now to find the length
a+b+a/2+b/2+(v-b/2-d/2)+c/2+d+c+d/2+(u-c/2)+(v-f/2)+e/2+f+e+f/2+(u-e/2-a/2)
which is (a+b+c+d+e+f)+u+v+u+v = 10+30=40
