
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Piravena needs to travel from city $D$ to city $E$, then from city $E$ to city $F$, and finally from city $F$ back to city $D$. The cities form a right-angled triangle with $F$ being the right-angle vertex. The distance from $D$ to $F$ is 4000 km, and from $D$ to $E$ is 5000 km. Traveling by bus costs $\$0.20$ per kilometer, and traveling by airplane involves a $\$120$ booking fee plus $\$0.12$ per kilometer. Determine the least expensive method for Piravena to travel among these cities and calculate the total cost.

Present the answer in LaTex format: \boxed{Your answer}
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