the angles below form a linear pair. m∠abc = ?°

Explanation:

Step1: Recall linear - pair property

Linear - pair angles are supplementary, i.e., their sum is 180°.

Step2: Set up the equation

Let (m\angle ABC=x). We know that (x + 57^{\circ}=180^{\circ}).

Step3: Solve for (x)

(x=180^{\circ}- 57^{\circ}). (x = 123^{\circ})

Answer:

123