Angle Pairs

∠1 and ∠3 can best be described as -

• complementary angles

• linear pair

• vertical angles

Answer explanation

The best description for ∠1 and ∠3 is 'vertical angles'. Vertical angles are pairs of opposite angles made by two intersecting lines. They are always equal.

∠a and ∠b can best be described as -

• complementary angles

• linear pair

• vertical angles

Answer explanation

Angles a and b are complementary angles. Complementary angles are pairs of angles with measures that add to 90 degrees.

∠a and ∠b can best be described as

• complementary angles

• linear pair

• vertical angles

Answer explanation

Angles a and b form a linear pair. A linear pair of angles are adjacent and supplementary. They are "built" along a line. Their measures add to 180 degrees.

The angle relationship shown is -

• complementary angles

• linear pair

• vertical angles

Answer explanation

The angle pair shown are complementary angles. This is because complementary angles, like the angles shown, have measures that add up to 90 degrees.

If m∠1 = 30°, then m∠3 = 

• 30°

• 60°

• 150°

Answer explanation

Angles 1 and 3 are vertical angles, which means that their measures are equal (the same). So if angle 1 has a measure of 30 degrees, angle 3 also has a measure of 30 degrees.

These angles ...

• are complementary

• are vertical angles

• form a linear pair

Answer explanation

The angles shown form a linear pair since they are both adjacent, meaning they share a common side, and are supplementary, meaning their measures add up to 180 degrees.

Find the missing angle.

• 40

• 50

• 140

Answer explanation

The missing angle in the question is 50 degrees. The angles shown are complementary angles, meaning their angles add up to 90 degrees. The equation would be

x+40=90.

Find the value of x.

• 28

• 62

• 118

Answer explanation

The angles shown are complementary angles, which means their angle measures will add to 90 degrees.

The equation would be

x+62=90

What is the measure of the missing angle?

• 108^o

• 72^o

• 180^o

Answer explanation

The angles shown form a linear pair. The measures of a linear pair of angles add to 180 degrees.

The equation is:

x+108=180

If the measure of ∠2 is 83°, what is the measure of ∠3?

• 97°

• 17°

• 83°

Answer explanation

Angles 2 and 3 form a linear pair. This means that their angle measures will add to 180 degrees. Your equation would be:

x + 83 = 180.