40 because 3+6+12 = 21 and 8+11+21 =40
285$ divided by 5$ = 57, 57 would be the correct answer.
I really don't understand your question that you asked 3 WEEKS ago.
Answer:
55 ft... The ladder must extend 55ft
Step-by-step explanation:

Answer:
simple
Step-by-step explanation:
t=b×h/2 and p= b×h