An angle that has a measure less than a right angle.

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1 Unit 1 Study Strategies: Two-Dimensional Figures Lesson Vocab Word Definition Example Formed by two rays or line segments that have the same 1 Angle endpoint. The shared endpoint is called the vertex. 1 Acute Angle An angle that has a measure less than a right angle. 1 Attributes A characteristic or property of an object such as color, shape, size, etc. 1 Right Angle An angle that forms a square corner and has a measure of Obtuse Angle An angle that has a measure greater than a right angle. 1 Straight Angle 1 Point 1 Line An angle in which two rays point in opposite directions so that they form a line. An exact location in space. A straight path of points that continues without end in both directions. A

2 1 Line Segment 1 Ray Part of a line between two endpoints. A part of a line, with one endpoint, that is straight and continues in one direction. A triangle with 3 acute angles. 2 Acute Triangle A triangle with 1 obtuse angle. 2 Obtuse Triangle A triangle with 1 right triangle. 2 Right Triangle 3 Intersecting Lines Lines in a plane that cross at exactly one point. Intersecting lines form 4 angles. 3 Parallel Lines 3 Perpendicular Lines Lines in a plane that are always the same distance apart. Parallel lines never intersect. Lines in a plane that intersect to form 4 right angles. A polygon with 4 sides and 4 angles. 4 Quadrilateral

3 4 Regular Polygon A polygon where all sides are equal and all angles are equal. 4 Trapezoid A quadrilateral with 1 set of parallel sides. 4 Parallelogram 4 Rhombus 4 Rectangle 4 Square A quadrilateral with 2 pair of parallel sides and 2 pair of sides with equal length. A quadrilateral with 2 pair of parallel sides and 4 sides of equal length. A quadrilateral with 2 pair of parallel sides, 2 pair of sides of equal length, and 4 right angles. A quadrilateral with 2 pair of parallel sides, 4 sides of equal length, and 4 right angles. 5 Line of Symmetry A fold line that divides a shape into two parts that are the same size and shape. 5 Line Symmetry What a shape has if it can be folded about a line so that its two parts match exactly.

4 6 Horizontal A line that runs left to right across a page. 6 Vertical A line that runs up to down across a page. 6 Diagonal A straight line that goes from one corner to another.

5 Lesson 1: Identify and draw points, lines, line segments, rays, and angles When measuring angles inside a polygon or quadrilateral measure the angles inside the shape. 1) How many obtuse angles does the polygon below have? 2) How many obtuse angles does the polygon below have? A. 0 B. 2 C. 3 D. 6 A. 0 B. 1 C. 2 D. 6

6 Lesson 3: Identify and draw parallel lines and perpendicular lines Attributes of Parallel Lines 1. Parallel lines can be 2 lines, line segments, or rays. 2. Parallel lines never cross so they do not create angles Attributes of Perpendicular Lines 1. Perpendicular lines can be 2 lines, line segments, or rays. 2. Perpendicular lines create 4 right angles. Lesson 4: Sort and classify quadrilaterals

7 Lesson 2: Classify Triangles 1) Acute Triangles have 3 acute angles. 2) Right triangles have 1 right angles and 2 acute angles. 3) Obtuse triangles have 1 obtuse angle and 2 acute angles. 4) Equilateral triangles have 3 acute angles. 5) Isosceles Triangles have 2 or 3 acute angles. 6) Scalene Triangles have 2 acute angles. Lesson 5: Line symmetry

8 Lesson 6: Find lines of symmetry Rule for regular polygons: The number of equal sides is the same number of lines of symmetry. For example: Rectangles have 2 pair of equal sides. Therefore, they have 2 lines of symmetry. Squares have 4 equal sides. Therefore, they have 4 lines of symmetry. 1) Try to find the number of lines of symmetry in these shapes Lesson 7: Solve shape pattern problems

9 Step 1: Find the rule of how the shape is growing. Step 2: Look for similarities and differences among the shapes to help you figure out the next shape. Figure 1: 5 squares Figure 2: 7 squares Figure 3: 9 squares The next figure will have 11 squares because, each figure increases by 2 squares. 1) A pattern is shown. 2) A shape pattern is shown. How many triangles are needed to create figure 5? Figure 1 Figure 2 Figure 3 How are the total number of squares in each figure related A. 5 to the figure s number? B. 7 C. 8 A. Add 2 to the figure D. 10 B. Add 3 to the figure C. Multiply the figure number by 2 D. Multiply the figure number by 3 3) A pattern is shown. Select all the figures that can be part of the pattern. A. D. B. C. E.