## Reflection: Intervention and Extension Right, Acute, & Obtuse Angles - Section 2: Teacher Demonstration

At first, this student, Confusion Between Scales, was confused about the scales. I asked probing questions at first, but then I realized that I need to approach this conference in another way. I stopped the video to provide a deeper level of intervention beyond questioning.

We walked up to the front board to discuss how to decompose a straight angle: Intervention. At first, I drew a straight angle and divided it in half. Then, I asked the student to identify the measurement of both angles. He quickly said, "90 degrees!" Then, I asked, what is the measurement of a straight line's angle? We added 90 + 90 off to the side. He said, "180 degrees!"

Then, I made another straight line angle decomposed into two angles. I labeled one angle as 45 degrees. I then asked, "What is the measurement of this other angle?" With time, he said, "135 degrees." All of a sudden, everything "clicked" for this student. This was the point that I realized the importance of teaching the properties of supplementary angles alongside protractor use!

Often, I'll provide an intervention for one student and then realize that all students could benefit from the same instruction (which was the case in this situation). So I provided a quick mid-workshop lesson on decomposing straight angles with the rest of the class: 180 Degrees Demonstration. I followed the same procedures as above, but then, students identified that there will always be a "Big" angle and a "Little" angle when you decompose a straight line's angle... unless both angles measure 90 degrees.

Intervention and Extension: Intervention and Extension

# Right, Acute, & Obtuse Angles

Unit 8: Geometry
Lesson 1 of 7

## Big Idea: Students will learn how to use a protractor and will construct definitions for right, acute, and obtuse angles.

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Standards:
Subject(s):
Math, obtuse angle, angles, supplementary angles, Triangles, angles (Constructions), quadrilateral, acute angles, protractor use, right angles, complementary angles, Polygon, shapes, classifying triangles
100 minutes

### Kara Nelson

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