Answer:
E= 11
Step-by-step explanation:
The answer is D
Base area: 9 x 7 = 63
63 x 5 = 315
a:) Integer Sequences
b:) 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, ...