Stage Three: Angles (Straight, Obtuse, Acute, and Right)

Angles Introduction

Angles are two rays with the same endpoint. They measure the rotation of these rays which are considered the sides of the angle. These rays have a common endpoint which is called the vertex. 

Angles can be a hard concept to understand when measuring, so it is important to know those fundamental building blocks of geometry: points, lines, and planes. When I was younger, I struggled a lot to understand angles and geometry in general for that matter. Without understanding the building blocks, you cannot understand geometry. 

Straight, Obtuse, Acute, and Right Angles

There are a few different types of angles to remember: straight, obtuse, acute, and right. A straight angle is exactly 180 degrees and an obtuse angle is greater than 90 degrees but less than 180 degrees. An acute angle is less than 90 degrees and a right angle is exactly 90 degrees.

A trick you can use to help your students remember the differences between these angles is to associate the pronunciation of the words with its meaning. OBtuse angles are big while acute angles are cute and small. Straight angles can only be 180 degrees while right angles can only be 90 degrees so they should be easier to comprehend.

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