2 PLANE FIGURESA plane is a flat surface that goes on and on in all directions.A plane figure is a flat geometric shape.POLYGONSA polygon is a closed plane figure made up of three or more line segments (sides) that are connected.
3 vertices A vertex is the point where two sides of a polygon meet. The plural of vertex is vertices.vertices
4 Polygons are named by the number of sides they have. A triangle has 3 sides.A quadrilateral has 4 sides.A pentagon has 5 sides.There are also names for polygons with seven sides, nine sides, and any number of sides!A hexagon has 6 sides.An octagon has 8 sides.
5 PERIMETERThe perimeter of a figure is the distance around the outside.What is the perimeter of each of these polygons?12 in.8 units6 in.6 in.9 units9 unitsP =36 in.P =37 units11 units12 in.15 m.5 m.P =39 m.16 ft.16 ft.5 m.4 m.P =50 ft.10 m.18 ft.
6 AREAThe area of a flat surface is the number of square units needed to cover the surface.What is the area of each of these polygons?Count the square units to find out.A =20 sq. unitsA =104 sq. units
7 AREAThe area of a flat surface is the number of square units needed to cover the surface.What is the area of each of these rectangles?Multiply to find out.4 units4 unitsA =8 x 13 =104 sq. unitsA =4 x 4 =16 sq. units
8 CIRCLESA circle is a closed curve that is made of points that are the same distance from the center.A line segment is a part of a line.A radius is any line segment that connects the center to a point on the circle.A diameter is any line segment that passes through the center of a circle, connecting two points on the circle.A diameter is twice as long as a radius.
9 CIRCLESThe circumference is the distance around a circle.The circumference of a circle is about 3 times the diameter.C = about 3 x d
10 CIRCLESThe area of a circle is the number of square units needed to cover the inside of the circle.Find the approximate area of a circle by counting the square units inside or by multiplying the radius times the radius times 3.A = about 3 x r x r
11 CIRCLES P = about ______ units. A = about ______ sq. units. 18 36 27 Find the approximate perimeters of the circles below.R = 3 unitsR = 6 unitsP = about ______ units.A = about ______ sq. units.183627P = about ______ units.A = about ______ sq. units.108
12 CONGRUENT FIGURESCongruent figures have the same size and shape.
13 SIMILAR FIGURESSimilar figures have the same shape. If they also have the same size, they are congruent.
14 MOVING PLANE FIGURESA slide (translation) moves a figure up, down, or over.
15 MOVING PLANE FIGURESA turn (rotation) rotates a plane figure.
16 MOVING PLANE FIGURESA flip (reflection) is a mirror image of a figure.
17 SYMMETRY A plane figure has symmetry if its halves match. If a plane figure has symmetry, it can be folded so its halves match. The fold is called a line of symmetry.
18 SYMMETRYHow many lines of symmetry do each of these plane figures have?
19 TESSELLATIONS (TILING) A tessellation completely covers the inside space of a plane figure, usually in some kind of organized pattern.
20 Now use the tiles to experiment Now use the tiles to experiment. Which tiles will tessellate a piece of math paper? Try squares, triangles, hexagons, etc. Will circles tessellate a plane figure? Explain your answer.
21 SOLID GEOMETRYA three-dimensional object is called a space figure or a solid.cubecylinderrectangular prismpyramidspherecone
29 GEOMETRY VOCABULARY TERM EXAMPLE SAY A A point is an exact location in space.Apoint AA line is a collection of points that go on and on in both directions. It has no endpoints.Cline BCA line segment is part of a line. It has two endpoints.line segment DEA ray is part of a line. It has one endpoint and continues on and on in one direction.FGray FGIntersecting lines are lines that pass through the same point.line HK intersects line JI at point LParallel lines are lines that never intersect.line JK is parallel to line BC.BBBD EHLIJKJKJ KB C
30 GEOMETRY VOCABULARYTwo intersecting lines that form four right angles are perpendicular to each other.ACBDLine BC is perpendicular to line AD.
31 GEOMETRY VOCABULARY Two rays meet at a vertex, forming an angle. An angle that forms a square corner is a right angle.An angle greater than a right angle is an obtuse angle.An angle less than a right angle is an acute angle.