• ## CHAPTER 10: TWO-DIMENSIONAL FIGURES

In Chapter 10 students will:

• draw and identify lines and angles
• classify shapes by properties of their lines and angles
• generate and analyze patterns

Vocabulary:

• line – a straight path of points that continues without end in both directions
• ray - a part of a line, with one endpoint, that is straight and continues in one direction
• acute angle – an angle that has a measure less than a right angle
• obtuse angle – an angle that has a measure greater than a right angle
• right angle – an angle that forms a square corner and has a measure of 90 degrees
• straight angle - an angle in which two rays point in the opposite directions so that they form a line
• line of symmetry - an imaginary line that divides a shape into two congruent parts
• line symmetry - what a shape has if it can be folded along a line so that its two parts match exactly

Chapter 10 Standards:
Geometry (4.G)
Draw and identify lines and angles, and classify shapes by properties of their lines and angles.  (CC.4.G)

1. Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures. (CC.4.G.1)
2. Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles. (CC.4.G.2)
3. Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry. (CC.4.G.3)

Operations and Algebraic Thinking (4.OA)

Generate and analyze patterns.

5. Generate a number or shape pattern that follows a given rule. Identify apparent features of the pattern that were not explicit in the rule itself. For example, given the rule "Add 3" and the starting number 1, generate terms in the resulting sequence and observe that the terms appear to alternate between odd and even numbers. Explain informally why the numbers will continue to alternate in this way. (CC.4.OA.5)

• Chapter 10 videos:

Lines, Rays, and Angles  (CC.4.G.1)*
Lesson 10.2  Classify Triangles  (CC.4.G.2)*
Lesson 10.3  Parallel and Perpendicular Lines  (CC.4.G.1)*