Answer:
The sum of all four angles of a quadrilateral is 360 degrees.
Let's denote the two unknown angles as 4x and 9x, where x is a constant.
We can set up an equation using the given information:
291 + 17 + 4x + 9x = 360
Simplifying the equation:
308 + 13x = 360
13x = 52
x = 4
So, the two unknown angles are:
4x = 16 degrees
9x = 36 degrees
Therefore, the measures of the two angles in a ratio of 4:9 are 16° and 36°.