A is the answer because I did befor
The pyhtagorean states that to find c, use the eqaution,

.
Substitute 1 for a and 20 for b;
c^2=1+400
c^2=401
c=
which is about 20.02
Hope this helps.
Answer:
8000•1.05 8000(1.05)¹
(8000•1.05)•1.05 8000(1.05)²
((8000•1.05)•1.05)•1.05 8000(1.05)³
(((8000•1.05)•1.05)•1.05)•1.05 8000(1.05)⁴
8000(1.05)^t
Step 2 they added instead of multiplied