Answer:
b = 12
Step-by-step explanation:
Complementary angles add to 90 degrees
a+b = 90
78+b = 90
Subtract 78 from each side
78-78+b = 90-78
b = 12
Carl needs to find the (B) Volume of the fish tank
Hope this helped!!
Subtract 5 each play so go backwards from zero and you should finish at -15