
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
Given vectors $\overrightarrow {a}$=(2cosθ, 1) and $\overrightarrow {b}$=(1, 2sinθ) where θ∈(0, π).
1. Find the value of θ if $\overrightarrow {a}$ is parallel to $\overrightarrow {b}$.
2. If $\overrightarrow {a} \cdot \overrightarrow {b} = \frac{2}{5}$, find the value of $|\overrightarrow {a} + \overrightarrow {b}|$.

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