Question

Find (angle) Then classify the triangle by its angles.

M (angle) 1 =

Answer 1

• m∠1 = 110°
• obtuse triangle

Explanation:

You want to find the measure of the angle designated as ∠1, given the other two have measures of 40° and 30°. You also want the classification of the triangle based on its angles.

Angle sum

The sum of angles in a triangle is 180°.

40° +∠1 +30° = 180°

∠1 = 110° . . . . . . . . . . . . subtract 70°

Triangle classification

The classification of a triangle as acute, right, or obtuse is based on the measure of its largest angle. If that angle is 90°, the triangle is a right triangle. If it is less, the triangle is acute; if it is more, the triangle is obtuse.

The angle measure 110° is more than 90°, so this triangle is an obtuse triangle.