Question

In the diagram ABD and BDC are supplementary, the measure of EDF = 9x, and the measure of ABD = (2x + 105).

Based on this information, which equation can be used to find the value of x?

Options:
1. 9x=2x+105
2. 2x+105+9x=180
3. 2x+105+9x=80
4. 2x+106-9x=90

Answer 1

2) 2x + 105 + 9x = 180

Explanation:

∠BDC = ∠EDF { vertically opposite angles are equal}

∠BDC = 9x

∠ABD + ∠BDC = 180 {supplementary}

2x + 105 + 9x = 180