Answer:
p - a - c = b
Step-by-step explanation:
p = a + b + c
subtract a and b from both sides to isolate c
p - a - c = a - a + b
+ c - c
3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45
1600 square feet