I think 4 most likely because if u take the middle of the 3 dots it would lave the last dot on the 4
Algebra is number 3 - You have subtracted the measure of angle HKI from the equation.
Transitive property of equality is number 2 - Because both pairs of angles equal 180 degrees, you can set them equal to each other.
Definition of congruence is number 4 - The congruence symbol is in the equation, which tells you that the two angles are congruent.
Angles forming a linear pair sum to 180 degrees is number 1 - 180 degrees is in the equations given and the angles all form linear pairs.
Hope this helps!! :)
Just guess and check. For example, for the first on the left, I guessed 3 to begin with. 3 + 3 + 3 = 9, but 10 + 3 = 13, so 3 is not the answer. I then guessed 5. 5 + 5 + 5= 15, and 10 + 5= 15, so star = 5.