Geometry Ms. Crusenberry 8-2013

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

What are these examples of?

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

What are these examples of?

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

Examples Acute Obtuse Right Straight Reflex

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

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

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

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?

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

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

Name the following

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

Name the following triangles

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

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

Name the following

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

Name the following

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

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

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

Coordinate plane

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