1. Geometry
Ms. Crusenberry
8-2013

2. Vocabulary Angle – two rays with the same endpoint
Geometry – the study of points, lines, angles, surfaces, and solids
Line segment – part of a line
Plane – a flat surface that extends forever in all directions
Ray – a line that has a beginning point but no end
Vertex – the point where two rays meet
Point – a designated place

3. What are these examples of?

4. Vocabulary
Parallel lines – lines that are always the same distance apart
Intersecting lines – lines that cross in the same plane
Perpendicular lines – intersecting lines that cross and form four right angles

5. What are these examples of?

6. Identifying Angles
Acute – less than a right angle: between 0 degrees and 90 degrees
Right – formed by two perpendicular rays measuring exactly 90 degrees
Obtuse – larger than a right angle but smaller than a straight angle: between 90 degrees and 180 degrees
Straight – two rays form a straight line measuring exactly 180 degrees
Reflex – larger than a straight angle measuring between 180 degrees and 360 degrees

7. Examples
Acute Obtuse Right Straight Reflex

8. Vocabulary & examples
Circle – a plane figure whose points are equally distant from the center
Degree – a measure of angles

9. Parts of a circle
Circumference (c)– the distance around the edge of the circle
Radius (r) – the distance from the center of the circle to its circumference
Diameter (d) – a chord that passes through the center of the circle
Chord – a straight line from one point on the circumference to another

10. Area & circumference
Diameter = 2r Radius = d/2 Area = 3.14 x r2 Circumference = 3.14 x d The fraction for 3.14 is 22/7

11. Practice If the diameter is 10, what is the radius?
What is the area of the circle, if the diameter is 6?
What is the circumference of the circle, if the radius is 5?
What is the diameter if the radius is 14?

12. Answers
Radius = d/2; 10 ÷ 2 = 5
A = 3.14 x r2 ; A = 3.14 x 9; A = 28.26
C = 3.14 x d; C = 3.14 x 10; C = 31.40
Diameter = 2r; 2 x 14 = 28

13. Polygons Number of Sides Name of Polygon 3 Triangle 4 Quadrilateral 5
Pentagon 6
Hexagon 7
Heptagon 8
Octagon 9
Nonagon 10
Decagon 12
dodecagon

14. Name the following

15. Triangles Name Definition Right triangle One angle is 90 degrees
Obtuse triangle
One angle is more than 90 degrees
Acute
All angles are less than 90 degrees
Scalene triangle
No sides are equal
Isosceles triangle
Two sides equal
Equilateral triangle
All three sides are equal

16. Name the following triangles

17. Triangle Measurement PQR There are 180 degrees in a triangle.
If angle P = 60, and angle Q = 50, what is the measurement of angle R?
PQR

18. Quadrilaterals
Parallelogram – a four sided polygon with two pairs of equal and parallel sides
Quadrilaterals – polygons with four sides
Rectangle – a four sided polygon with four right angles and the opposite sides are equal
Rhombus – a polygon with four equal sides and the opposite angles are equal
Square – a polygon with four equal sides and four right angles
Trapezoid – a four sided polygon with one pair of parallel sides and one pair of sides that are not parallel

19. Name the following

20. Solid figures
Prism – a sold figure with two parallel faces that are polygons of the same shape
Cube – a prism with square sides and faces
Pyramid – a solid figure with a base that is a polygon and triangular sides
Cylinder – a solid figure with two equal circular bases that are parallel
Cone – a sold figure with a circular base connected to a vertex
Sphere – a solid figure with a curved surface in which all points on the surface are equal distance from the center

21. Name the following

22. Similarity & congruence
Similar means having the same shape but a different size Congruence means having exactly the same shape and the same size.

23. Reflection & translation
Reflection aka flip (forms a mirror image) Translation (a move to another position without rotating or reflecting)

24. Rotation/turn
A turn is a certain number of degrees around a fixed point.

25. Coordinate plane

26. Let’s practice drawing coordinate points
(1, 2)
(-3, 5)
(7, -10)
(-2, -2)