
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
The median  $BM$  is drawn in the triangle  $ABC$ . It is known that  $\angle ABM = 40 {} ^ \circ$  and  $\angle CBM = 70 {} ^ \circ $  Find the ratio  $AB: BM$ .

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