Angles, Triangles and Quadrilaterals Overview
Before students can effectively communicate their ideas about geometric shapes they must have a vocabulary with which to discuss the properties of those shapes. This vocabulary is best developed through experience. In lessons 1 and 2 students will draw triangles, review vocabulary as relates to triangles and then classify triangles. Lessons 3, 4, 5, and 6 are designed to review and reinforce concepts of geometric properties and geometric vocabulary of quadrilaterals. The unit project will be introduced in lesson 7 and that project will take several class periods.
Lesson 1: What Makes a Triangle a Triangle? Drawing and Sorting Triangles
Students will use a sorting activity to review and reinforce definitions of geometric vocabulary.
Lesson 2: Classifying Triangles by Side Length and Angle
Students will use a sorting activity to explore and analyze these types of triangles: scalene, isosceles, equilateral, acute, right and obtuse.
Lesson 3: Building Quadrilaterals
Students will use manipulatives to make quadrilaterals. Students will analyze the shapes that they have made and use appropriate vocabulary to describe and classify them.
Lesson 4: Sorting Quadrilaterals
Students will analyze the properties of quadrilaterals and will use appropriate vocabulary to describe and classify quadrilaterals into groups and subgroups.
Lesson 5: Organizing Quadrilaterals, A Quadrilateral Family Tree
Students will analyze the properties of quadrilaterals and use their understanding of those properties to organize quadrilaterals into a family tree.
Lesson 6: Analyzing the Quadrilateral Family Tree
Students will analyze the properties of quadrilaterals and use their understanding of those properties to classify the shapes.
Lesson 7: The Important Book
Using their understanding of the properties of triangles and quadrilaterals, the students will create a book.
Benchmarks and Standards
Measurement
Grade 6
0507 Benchmark
D. Identify, describe and classify types of line pairs, angles, twodimensional figures and threedimensional objects using their properties.
Y2003.CMA.S03.G0507.BD.L06.I01 Characteristics and Properties /
01. Classify and describe twodimensional and threedimensional geometric figures and objects by using their properties; e.g., interior angle measures, perpendicular/parallel sides, congruent angles/sides.
Y2003.CMA.S03.G0507.BD.L06.I02 Characteristics and Properties /
02. Use standard language to define geometric vocabulary: vertex, face, altitude, diagonal, isosceles, equilateral, acute, obtuse and other vocabulary as appropriate.
Y2003.CMA.S02.G0507.BC.L06.I03 Use Measurement Techniques and Tools /
03. Estimate perimeter or circumference and area for circles, triangles and quadrilaterals, and surface area and volume for prisms and cylinders by:

Estimating lengths using string or links, areas using tiles or grid and volumes using cubes;

Measuring attributes (diameter, side lengths or heights) and using established formulas

for circles, triangles, rectangles, parallelograms and rectangular prisms.
