40394

I did the last part of this question.

Every part opposite to b = b

Every part opposite a = a

You can give the opposite to b the name w (width)
And the opposite to a the name h (height)

So, there is every w added together = b
And every h added together = a

There is the original a + a(from Hs)
and b + b(from Ws)

Also, there are 2 Cs, so 2c

So, 2a+2b+2c is the perimeter of the whole yellow shape!