So the ratio of boys to girls is 12:24.. now, is that an equivalent ratio as 2 boys for 4 girls? or 2:4? let's see.

you could start simplifying the 12/24 fraction by dividing by some common multiple, say 2, and get 6/12, then divide by 3 and get 2/4 and stop there.
then you'll notice that 12/24 is really 2/4 in disguise.
Answer:
f= -14
Step-by-step explanation:
Use pythagorians theorem a^2 + b^2 = c^2. 4^+20^ = 20.40 feet. The ladder is 20.40 feet long.