Answer:
4 + 60 + 300 + NaN + 70000 + 600000 + 1000000 + NaN + 900000000
Answer is in the pic above. Theorems used:
Exterior angle theorem
Inscribed angle theorem.

Average = (A₁+A₂+A₃+A₄+A₅)/5. Since average = 20 (GIVEN), then:
20 = (A₁+A₂+A₃+A₄+A₅)/5
Or (A₁+A₂+A₃+A₄+A₅) = 20x5
(A₁+A₂+A₃+A₄+A₅) = 100