Answer:
Part A: yes
Part B: yes
Part C: yes
Explanation:
Part A:
77² + 420² = 427²
5,929 + 176,400 = 182,329
182,329 = 182,329
---------------------------------------------------------
Part B:
279² + 440² = 521²
77,841 + 193,600 = 271,441
271,441 = 271,441
----------------------------------------------------------
Part C:
39² + 760² = 761²
1,521 + 577,600 = 579,121
579121 = 579,121
----------------------------------------------------------