Lessons 6 & 7 (Angle Pairs and Triangles)

Front

What is an exterior angle in a triangle?

Back

An exterior angle is formed by one side of a triangle and the extension of an adjacent side. It is equal to the sum of the two remote interior angles.

Front

Define corresponding angles.

Back

Corresponding angles are pairs of angles that are in similar positions at each intersection where a straight line crosses two others. If the lines are parallel, corresponding angles are equal.

Front

What are remote interior angles?

Back

Remote interior angles are the two angles inside a triangle that are not adjacent to a given exterior angle.

Front

If m∠1 = 30°, what is m∠3 if they are corresponding angles?

Back

m∠3 = 30° (because corresponding angles are equal).

Front

What is the sum of the interior angles of a triangle?

Back

The sum of the interior angles of a triangle is always 180°.

Front

How do you find the measure of an angle if you know the measures of the other two angles in a triangle?

Back

Subtract the sum of the known angles from 180°. For example, if m∠A = 50° and m∠B = 60°, then m∠C = 180° - (50° + 60°) = 70°.

Front

What is the relationship between interior and exterior angles?

Back

An exterior angle is equal to the sum of the two remote interior angles.

Front

Define vertical angles.

Back

Vertical angles are the angles opposite each other when two lines intersect. They are always equal.

Front

What is the measure of angle b if it is an exterior angle and the remote interior angles are 20° and 30°?

Back

m∠b = 20° + 30° = 50°.

Front

If m∠2 = 131°, what is the measure of its corresponding angle?

Back

m∠2 = 131° (because corresponding angles are equal).