Question

find ( mangle1 ). then classify the triangle by its angles.( mangle1=square^{circ} ).the triangle can be classified by its angles as

Explanation:

Step1: Use the triangle angle - sum theorem

The sum of the interior angles of a triangle is \(180^{\circ}\). Let \(m\angle1=x\). Then \(x + 78^{\circ}+31^{\circ}=180^{\circ}\).

Step2: Solve for \(x\)

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Step3: Classify the triangle by its angles

Since all angles (\(71^{\circ}\), \(78^{\circ}\), \(31^{\circ}\)) are less than \(90^{\circ}\), the triangle is an acute triangle.

Answer:

\(m\angle1 = 71^{\circ}\). The triangle can be classified by its angles as an acute triangle.