
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
In the quadrilateral  $ABCD$ , the angles  $B$  and  $D$  are right . The diagonal  $AC$  forms with the side  $AB$  the angle of  $40^o$ , as well with side  $AD$  an angle of  $30^o$ . Find the acute angle between the  diagonals  $AC$  and  $BD$ .

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