Angle Definitions

If m<1 is 70 degrees, what is the m<4? (refer to the diagram)

110 degrees (because they are supplementary angles)

If m<2 is 130 degrees and m<4 = 10x, what is the value of x? (refer to diagram)

130 = 10x because they are vertical angles; divide by 10 on both sides; x = 13

Straight Angle

180 degree angle

If m<1 = 70 degrees, what is the m<3? (refer to the diagram)

70 degrees (because they are vertical angles)

Names two pairs of vertical angles (refer to the diagram)

<1 and <3; <2 and <4

If m<2 = 2x + 50 and m <3 is 60 degrees, what is the value of x? (refer to diagram)

<2 and <3 are supplementary. If m<3 is 60, then the m<2 must be 120. So, 2x + 50 = 120. Subtract 50 from both sides. Now you have 2x = 70. Divide both sides by 2. x = 35.

Name two pairs of supplementary angles (refer to the diagram)

Any of these two pairs: <1 and <2; <2 and <3; <3 and <4; <4 and <1

Right Angle

angle that measures 90 degrees

Acute Angle

angle that measures less than 90 degrees

Obtuse Angle

angle with measure greater than 90 degrees and less than 180 degrees

Adjacent Angles

angles with a common endpoint that share a side (ray)

Area

number of square units in a 2D figure

Supplementary Angles

two angles who sum is 180 degrees

Complementary Angles

two angles whose sum is 90 degrees

Vertical Angles

two opposite angles with a common endpoint created by intersecting lines . Vertical angles have equal measures.

Angle

union of two rays with a common endpoint