Angle Relationship Equations

What Equation would you use to find x?

• 123 + 3x

• 123 + 3x = 180

• 123 + 3x = 90

What Equation would you use to find r?

• 2r + 6 = 89

• 2r + 90 = 89

• 2r + 3 = 89

• 2r + 3 + 89 = 180

Tell whether the angles are complementary or supplementary. Then find the value of x.

• Complementary; x=25
• Complementary; x=5
• Supplementary; x=25
• Supplementary; x=5

Are these angles

• equal (congruent)

• complementary

• supplementary

What equation would you use to find the value of x?

• 2x-6=7x+4

• 2x-6+7x+4=90

• 2x-6+7x+4=180

Are these angles

• equal-- so they are congruent

• supplementary-- so they add up to 90

• supplementary--- so they add up to 180

These are vertical angles -- they are opposite one another. So are they

• supplementary-- add up to 180

• complementary-- add up to 90

• congruent-- so they are equal

Vertical angles are opposite one another, so the equation we should use to solve is

• 140 + 6x + 120 = 180

• 140 = 6x + 20

• 140 + 6x + 20 = 90

These angles form a line, that means that together they equal 180 degrees. So, the equation we should use is

• 2x + 10 = 4x +20

• 2x + 10 + 4x + 20 = 180

• 6x = 30

_{These are Complementary angles, that means that together they equal 90. Find x.}

• 15

• 25

• 75

• 90