Question

what is the value of d? 78.4° 73.1° d save answer use previous answer

Explanation:

Step1: Recall angle - sum property

The sum of angles around a point is $360^{\circ}$.

Step2: Set up the equation

Let the three given angles be $78.4^{\circ}$, $73.1^{\circ}$, and $d$. Then $78.4 + 73.1+d + \text{(the other two angles)}=360$. Since the other two angles are vertical to the given two non - $d$ angles, we can also directly use the fact that $78.4+73.1 + d=180$ (because the angles form a linear - pair or we consider the semi - circle of angles around the intersection point).

Step3: Solve for $d$

$d=180-(78.4 + 73.1)$.
$d=180 - 151.5$.
$d = 28.5$.

Answer:

$28.5$