Brunswick Third Grade Team Math Unit 4 Dear Parents, Students will now be working on geometry. This unit has a lot of vocabulary and requires them to identify geometric terms. We will continue to work very hard in class to master these skills. This packet will provide details of the concepts we will be teaching during our fourth math unit. Please know that this is only a resource to keep you informed on the concepts we are learning in class. Please remember that these concepts will be introduced over time. This is designed to allow parents the opportunity to practice and reinforce these skills at home. Thank you for your help this year! Three Dimensional Figures: A three dimensional figure is a shape that had has length, width, and height. Students will need to be able to identify the following three dimensional shapes: Cube: A 3-dimensional figure with 6 square faces. Cylinder: A 3-dimensional figure with 2 congruent faces that are circular. Rectangular Prism: A 3-dimensional figure with 6 rectangular sides. Cone: A pointed, 3-dimensional figure with a circular base. Sphere: A 3-dimensional figure that has the shape of a ball. Pyramid: A 3-dimensional figure that is shaped by triangles on a base. Face: A flat side of a 3 dimensional figure. Edge: A line segment where two faces of a 3-dimensional figure meet. Two Dimensional Figures: A figure on a plane. It only has length and height (not width). Polygons: Polygons are closed figured with straight sides. Tri - three Triangle Quad - four Quadrilateral Penta – five Pentagon Hexa – six Hexagon Hepta – seven Heptagon Octa – eight Octagon Nona – nine Nonagon Deca – ten Decagon Triangles: A polygon with three sides and three angles. Isosceles Triangle: A triangle having two sides of equal length. Equilateral Triangle: A triangle having all three sides of equal length. The angles of an equilateral triangle all measure 60 degrees. Scalene Triangle: A triangle having three sides of different lengths. Right Triangle: A triangle with one right angle. Acute Triangle: A triangle having three acute angles. Obtuse Triangle: A triangle having an obtuse angle. One of the angles of the triangle measures more than 90 degrees. Quadrilaterals: A polygon with 4 sides. Square: A polygon that has four equal sides and four equal (right) angles (right angles). Rectangle: A polygon with four sides and four right (equal) angles. The opposite sides are the same length. Rhombus: A quadrilateral with 4 sides the same length. Parallelogram: A quadrilateral with opposite sides parallel. Trapezoid: A quadrilateral with exactly one pair of parallel sides. Lines, Line Segments, Rays, & Angles: Ray: A 2-dimensional figure that has one endpoint and goes without end in one direction. A ray is shown with an endpoint and an arrow at one end. Line: A straight path that goes in two directions without end (forever and ever). The line will have arrows on both ends. Line Segment: A straight path that has 2 endpoints. It is a piece of a line. Angle: A figure formed when two rays or lines meet at the same point. Right Angle: An angle that forms a square corner (90º) Obtuse Angle: An angle greater than a right angle (90 º) Acute Angle: An angle less than a right angle (90 º) Vertex/vertices: The vertex of an angle is the point where the two rays that form the angle intersect. Parallel Lines: Lines that do not cross. Intersecting lines meet or cross at a common point. Congruent Figures: Congruent shapes are same shape and same size. Similar Figures: Shapes that are the same shape but may be a different size. Line of Symmetry: Is a line on which a figure can be folded so that both sides match. Circle: A closed, 2-dimensional figure having all points the same distance from a given point. Radius: A line from the center of a circle to a point on the circle. Diameter: A line touching 2 points on a circle and passing through the center of a circle. Perimeter: The distance around an object or shape. This is measured in units. (units, inches, feet, centimeters, etc.) Example: 5 + 4 + 2 + 7 + 1 = 19 units Area: The number of square units needed to cover a region or figure. This is measured in square units. Example: 5 + 5 + 5 + 5 = 20 square units Volume: The amount of space that a 3-dimensional figure encloses. This is measured in cubic units. Example: 6 + 6 = 12 cubic units Translations (slide) to move a figure along a line. Slide! Reflection (flip) a movement of a figure across a line, producing a mirror image. Flip! Rotation (turn) turn a figure. Tessellation repeated shapes that cover a flat surface without overlapping or leaving any gaps. Chapter 4 Concept Checklist The following is a checklist you may want to use to track your child’s progress. Again this is an optional form for you, designed to keep you informed of your child’s progress. It does not need to be completed but is simply a resource available to you if you wish to utilize it. Concept Mastered 3-dimensional figures 2-dimensional figures, Polygons Lines, Line Segment, Rays Angles Triangles Quadrilaterals Congruent/Similar Symmetry Perimeter Area Volume Problem Solving .