Question

solve for the value of d.
answer
attempt 3 out of 3
d =

Explanation:

Step1: Set up the equation

Since the sum of the three angles is \(180^{\circ}\) (a straight - line angle) and one of the angles is \(90^{\circ}\) (right - angle), we have \((6d + 7)+(9d - 7)+90=180\).
Simplify the left - hand side: \(6d+7 + 9d-7+90=(6d + 9d)+(7 - 7)+90=15d+90\). So the equation becomes \(15d+90 = 180\).

Step2: Solve for \(d\)

Subtract \(90\) from both sides of the equation: \(15d+90-90=180 - 90\), which gives \(15d=90\).
Divide both sides by \(15\): \(d=\frac{90}{15}\).

Answer:

\(d = 6\)