Answer:
Definition of reference angle:
The smallest angle that the terminal side of a given angle makes with the x-axis.
Given that the angle theta is
![\theta=290^0](https://img.qammunity.org/2023/formulas/mathematics/college/je005fd5cj72h6bp4bsbbbf9ucaf2yy9ve.png)
Hence,
To figure out the reference angle, we will have
Assuming a base side for the angle along the X-axis, the reference angle is the smallest acute angle as measured from the X-axis
![\begin{gathered} reference\text{ angle =360}^0-290^0 \\ reference\text{ angle =70}^0 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5xlp8wnkhp5bjf0clllsu6arh5ploehtjk.png)
(yes; I know this is not technically an acute angle, but it is the smallest positive angle).
Therefore,
The reference angle is = 70°