th 7 grade Geometry 1 Mrs S Brown

th 7 grade Geometry (1) Mrs. S. Brown

Day 1 Angles: • 3

Acute Angles: An Acute Angle is less than 90° This is an acute angle:

Right Angle: A right angle is an internal angle which is equal to 90° This is a right angle:

Obtuse Angles: • An Obtuse Angle is more than 90° but less than 180° • This is an obtuse angle !

Straight Angles: • A straight angle is 180 degrees This is a straight angle :

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Vertical Angles: • Vertical Angles are the angles opposite each other when two lines cross. They are always equal. In this example a° and b° • are vertical angles.

Vertical Angles: Vertical Angles are ALWAYS equal or congruent! ∠ 1= 18

Vertical Angles: Solve for x: 11 y-36=63 +36 11 y=99 y=9

Adjacent Angles: • Two angles are Adjacent when they have a common side and a common vertex (corner point), and don't overlap.

Adjacent Supplementary • Adjacent Supplementary Angles two angles that have a common side and whose other sides lie on the same line. Their sum is always 180. Because they form a straight angle. 45+135=180

Adjacent Supplementary: Solve for x: 5 x+10+70=180 5 x+10 5 x+80=180 -80 5 x=100 x=20

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Day 2 • Complementary Angles: • Two angles are Complementary when they add up to 90 degrees (a Right Angle ). • ∠AOC + ∠COB are complementary • 60 + 30 = 90

Finding X X + 62=90 -62 X=28 degrees

Finding x 5 x +25=90 5 x+25 =90 -25 5 x=65 X=13 5 x

Supplementary Angles: Two Angles are Supplementary when they add up to 180 degrees. These two angles are Supplementary Angles, because they add up to 180°: ∠a and ∠b =180 45+135=180 a b

Find the Missing Angle: ∠b and ∠c are Supplementary. If ∠b= 50 degrees, what is the measurement of ∠c? 50+c=180 -50 c=130 degrees

Finding X: 4 x+10+130=180 4 x+140=180 -140 4 x=40 X=10 4 x+10

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Day 3: Classify Triangles • Equilateral triangle: A triangle with all three sides equal in measure. In Figure 1, the slash marks indicate equal measure.

Classify Triangles Isosceles triangle: A triangle in which at least two sides have equal measure

Classify Triangles Scalene triangle: A triangle with all three sides of different measures

Classify Triangles Right triangle: A triangle that has a right angle in its interior, the other two angles are acute.

Classify Triangles Obtuse triangle: A triangle having an obtuse angle, the other two angles are acute.

Classify Triangles • Acute triangle: A triangle having all acute angles

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Day 4: Triangle Interior Angles • Triangles • The Interior Angles of a Triangle add up to 180° • 60 +30+90= 180

Finding the Missing Angle: 32+24+x=180 56+x=180 -56 x=124

Check your work! • They three angles should add up to 180! • 32+24=180 • There is always 180 degrees inside of a triangle.

Finding x Remember a right angle is 90 degrees! 90+2 x+1+5 x+5=180 96+7 x=180 -96 7 x= 84 x=12

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