Question

what is the value of d? (with an image of intersecting lines showing angles 48°, 78°, and angle d)

Explanation:

Step1: Recall angle sum on a straight line

A straight line forms a \(180^\circ\) angle. So, the sum of \(d\), \(78^\circ\), and \(48^\circ\) should be \(180^\circ\).
\[d + 78^\circ + 48^\circ = 180^\circ\]

Step2: Simplify the left - hand side

First, add \(78^\circ\) and \(48^\circ\): \(78 + 48=126\), so the equation becomes
\[d+126^\circ = 180^\circ\]

Step3: Solve for \(d\)

Subtract \(126^\circ\) from both sides of the equation:
\[d=180^\circ - 126^\circ\]
\[d = 54^\circ\]

Answer:

\(54\)