Question

Hat is the measure of x?
X = [?]
D
126

Answer 1

since those are angles on a straight line.

we work out as follows

• x+126°=180°
• x+126°-126°=180°-126°
• x=54°

Answer 2

∠DBA and ∠DBC are making linear pair.

Linear pair of angles are formed when two lines intersect each other at a single point.

• The sum of angles of a linear pair is always equal to 180°

`\rm \large\longrightarrow \: \: x \: + \: 126 \degree \: = \: 180 \degree`

`\rm \large\longrightarrow \: \: x \: = \: 180 \degree \: - \: 126 \degree`

`\rm \large\longrightarrow \: \: x \: = \: 54 \degree`