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Complementary angles. When two angles add up to 90° they are called complementary angles . a. b. a + b = 90°. Angle a and angle b are complementary angles . Supplementary angles. When two angles add up to 180° they are called supplementary angles . b. a. a + b = 180°.
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Complementary angles When two angles add up to 90° they are called complementary angles. a b a + b = 90° Angle a and angle b are complementary angles.
Supplementary angles When two angles add up to 180° they are called supplementary angles. b a a + b = 180° Angle a and angle b are supplementary angles.
Lines in a plane … or they are parallel. We use arrow heads to show that lines are parallel. Parallel lines will never meet. They stay an equal distance apart. This means that they are always equidistant. Where do you see parallel lines in everyday life?
Perpendicular lines What is special about the angles at the point of intersection here? a a = b = c = d b d Each angle is 90. We show this with a small square in each corner. c Lines that intersect at right angles are called perpendicularlines.
Corresponding angles There are four pairs of corresponding angles, or F-angles. a a b b d d c c e e f f h h g g ∠ d= ∠ hbecause Corresponding angles are equal
Corresponding angles There are four pairs of corresponding angles, or F-angles. a a b b d d c c e e f f h h g g ∠ a= ∠ ebecause Corresponding angles are equal
Corresponding angles There are four pairs of corresponding angles, or F-angles. a b d c c e f h g g ∠ c= ∠ gbecause Corresponding angles are equal
Corresponding angles There are four pairs of corresponding angles, or F-angles. a b b d c e f f h g ∠ b= ∠ fbecause Corresponding angles are equal
Alternate angles There are two pairs of alternate angles, or Z-angles. a b d d c e f f h g ∠ d = ∠f because Alternate angles are equal
Alternate angles There are two pairs of alternate angles, or Z-angles. a b d c c e e f h g ∠ c= ∠ ebecause Alternate angles are equal
Co-Interior angles There are two pairs of co-interior, or C-angles. a b d c c e e f h g ∠ c + ∠f = 180 ⁰because The sum of C angles is 180⁰
Co-interior angles There are two pairs of co-interior angles, or C-angles. a b d c c e e f h g ∠ d + ∠ e = 180because The sum of C angles is 180⁰
Opposite angles There are two pairs of opposite angles, or X-angles. a b d c c e e f h g ∠ a=∠ c ∠ b= ∠ d Opposite angles are equal
b f d e h c g a Q #1 corresponding or F • ∠ b and ∠ h are _____________________angles • ∠ e and ∠ c are ______________________ angles • ∠ e and ∠ h are ______________________angles • ∠ f and ∠ d are ______________________angles co-interior or C alternate or Z opposite or X
w y x 140⁰ Q #2 ∠ x = ∠ w = ∠ y = 140⁰ (x-angle) 180 – 140 ⁰= 40 (supplementary-angle) 140 ⁰ (z-angle)