Question

step angle reason 1 m∠c = 55° given 2 m∠b = 44° given try m∠cab = 81° select a reason select a reason vertical angles linear pair (or triple) congruent angles sum of angles in a triangle sum of angles in a quadrilateral base angle of an isosceles triangle angle bisector definition corresponding angles alternate interior angles alternate exterior angles same - side interior angles angle addition postulate angle subtraction postulate perpendicular lines form right angles

Explanation:

Step1: Recall angle - sum property

The sum of the interior angles of a triangle is 180°.

Step2: Set up the equation

Let \(m\angle CAB=x\). Then \(x + m\angle B+m\angle C=180^{\circ}\).

Step3: Substitute given values

We know \(m\angle C = 55^{\circ}\) and \(m\angle B = 44^{\circ}\), so \(x+44^{\circ}+55^{\circ}=180^{\circ}\).

Step4: Solve for \(x\)

\(x=180^{\circ}-(44^{\circ} + 55^{\circ})=180^{\circ}-99^{\circ}=81^{\circ}\).

Answer:

The reason is Sum of angles in a triangle.