Geometry Classify TwoDimensional Figures TOPIC 16 Lesson 16

Geometry: Classify Two-Dimensional Figures TOPIC 16

Lesson 16. 1 Classify Triangles Essential q Question: How can you classify triangles?

Lesson 16. 1 Build on What You Know VOCABULARY A polygon is a flat shape made of line segments forming a closed figure

Lesson 16. 1 Build on What You Know Create a chart like this in your notes

Lesson 16. 1 Build on What You Know Sort these shapes into your chart

Lesson 16. 1 Build on What You Know How did you do?

Lesson 16. 1 Build on What You Know Polygons are named for their number of sides Key idea

Lesson 16. 1 Build on What You Know Sides and angles are equal

Lesson 16. 1 Classifying Triangles Just like here in our world, in Polygon Land (which is flat by the way), when baby triangles are born, they are given a first name and a middle name. Their first name is based on their sides, and their middle name is based on their angles.

Lesson 16. 1 Classifying Triangles rt in a h is c s! h t t Pu ur note yo “FIRST NAME” E” NAM E L D D I “M

Lesson 16. 1 Classifying Triangles Let’s name some baby triangles! Now let’s look at his angles. First let’s look at this baby’s sides. They are all acute. He has 2 equal sides. So his first name is ISOSCELES So his middle name is ACUTE. My name is ISOSCELES ACUTE

Lesson 16. 1 Classifying Triangles Now let’s look at her angles. Now look at this baby girl’s sides. She has a 90° right angle. She has NO equal sides. So her first name is SCALENE. So her middle name is RIGHT. My name is SCALENE RIGHT

Lesson 16. 1 Classifying Triangles Now let’s look at his angles. What do you notice about this baby boy’s sides? They are all acute. He has ALL equal sides. So his first name is EQUILATERAL. My name is EQUILATERAL ACUTE So his middle name is ACUTE.

Lesson 16. 1 Classifying Triangles Now let’s look at his angles. What do you notice about this baby boy’s sides? He has one obtuse angle. Two of them are equal. So his first name is ISOSCELES My name is ISOSCELES OBTUSE So his middle name is OBTUSE.

Lesson 16. 1 Classifying Triangles KEY IDEA

Lesson 16. 1 Classifying Triangles KEY IDEA

Lesson 16. 1 Classifying Triangles Additional Resources Classifying Triangles with Mr. Peters https: //www. youtube. com/watch? v=j. Xcz. CSp. Wqdg Math Antics Triangles https: //www. youtube. com/watch? v=m. Le. Na. Zcy-h. E Number Rock Triangle Song https: //www. youtube. com/watch? v=JQUTVg. T 9 RXY

Guided Practice 16. 1 No, because all of the angles of a triangle always add up to 180° No, by definition an equilateral triangle has all sides of equal length. Equilateral Acute Isosceles Right

Guided Practice 16. 1 Isosceles Acute Equilateral Acute Scalene Right Isosceles Obtuse Isosceles Acute

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