Unit 6

Geometry

Grade 4

Math

 

Description:

In unit 6, students will learn that angles are geometric shapes made of two rays.  Students will learn to measure angles in degrees using a circular protractor and to sketch angles of a certain measure.  Students will learn three types of angles, right, acute and obtuse.  Students will learn that the sum of angle measurements around a point is 360 degrees and the sum of angle measurements on a line is 180 degrees.  Students will use this knowledge to find unknown angles.  Students will solve addition and subtraction problems to find unknown angles on a diagram in real world and mathematical problems.

Students build, draw and analyze two dimensional shapes in geometry.  Students will draw and identify points, lines, line segments, rays, angles, and perpendicular and parallel lines.  Students will use their knowledge of perpendicular and parallel lines and angle type to classify two-dimensional figures. Students will identify line-symmetric figures and draw lines of symmetry.

Louisiana Student Standards for Mathematics (LSSM)

 

Additional Cluster: MD:  Measurement and Data

 

Geometric measurement:  understand concepts of angle and measure angles.

 

4.MD.5

 

 

Recognize angles as geometric shapes that are formed whenever two rays share a common endpoint, and understand concepts of angle measurement:

a.    An angle is measured with reference to a circle with its center at the common endpoint of the rays, by considering the fraction of the circular arc between the points where the two rays intersect the circle.

b.    An angle that turns through 1/360 of a circle is called a “one-degree angle,” and can be used to measure angles.

c.    An angle that turns through n one-degree angles is said to have an angle measure of n degrees.

 

4.MD.6

 

Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure.

 

4.MD.7

 

Recognize angle measure as additive. When an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts. Solve addition and subtraction problems to find unknown angles on a diagram in real world and mathematical problems, e.g., by using an equation with a letter for the unknown angle measure.

 

Measurement and Data

Related area to operations of multiplication and addition

4.MD.8

 

Recognize area as additive. Find areas of rectilinear figures by decomposing them into non-overlapping rectangles and adding the areas of the non-overlapping parts, applying this technique to solve real-world problems.

Additional Cluster: G: Geometry

 

Draw and identify lines and angles, and classify shapes by properties of their lines and angles.

 

4.G.1

 

Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.

 

4.G.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.

 

4.G.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.

 

 

Enduring Understandings:

 

  • Geometric figures can be analyzed based on their properties.
  • Geometric figures can be classified based on their properties.
  • Lines of symmetry for a two-dimensional figure occur when a line can be drawn across the figure such that the figure can be folded along the line into matching parts.

Essential Questions:

 

·   How do we use geometry to help us make sense of the world?

·   What is unique about each geometric shape?

·   How do we talk about and classify different shapes?

·   How do I measure geometric shapes?

·   What are the geometric objects that make up figures?