.45x+.55x=200
Combine like terms
1x=200
So x is 100
Or you can do 45%+55%=100%
And 100% of 200 is 200
B, c, and e
6x6=36
9x9=81
11x11=108
Answer: 
<u>Do Keep Change Flip (KCF)</u>
Keep: 
Change: ÷ into ×
Flip:
into 
<u>Multiply</u>

20^2 + 13.5^2 = c^2
582.25 = c^2
√582.25 = c
24.1 = c
hope this helps :)