Question

calculate the missing measurement.
∠y = ?°

Explanation:

Step1: Recall the triangle - angle sum theorem

The sum of the interior angles of a triangle is \(180^{\circ}\). Let \(\angle X = 30^{\circ}\), \(\angle Z=115^{\circ}\), and \(\angle Y = y\). Then the formula is \(\angle X+\angle Y+\angle Z = 180^{\circ}\).

Step2: Solve for \(\angle Y\)

Substitute the known values into the formula: \(y + 30^{\circ}+115^{\circ}=180^{\circ}\).
First, simplify the left - hand side: \(y+145^{\circ}=180^{\circ}\).
Then, subtract \(145^{\circ}\) from both sides: \(y=180^{\circ}-145^{\circ}\).

Answer:

\(35^{\circ}\)