Question

look at the diagram. which equation can be used to solve for x? 22x + 90 = 180 22x = 90 4x + 18 = 180 4x + 18 = 90 solve for x. x =

Explanation:

Step1: Identify angle - sum relationship

Observe that $\angle ADB = 18^{\circ}$, $\angle CDE=4x^{\circ}$, and $\angle BDC = 90^{\circ}$. The sum of $\angle ADB$ and $\angle CDE$ is equal to $\angle BDC$ because $\angle ADB+\angle BDC+\angle CDE = 180^{\circ}$ and $\angle BDC = 90^{\circ}$, so $18 + 4x=90$.

Answer:

$4x + 18 = 90$, $x = 18$