Let's start with a test!
The Test
Here is a -question, multi-choice test for the "Obtuse Angles" lesson. The pass mark is 90%. Don't worry! All the information you need to pass is in the lesson section under the test.show as slides
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The Lesson
An obtuse angle is greater than a right angle and less than a straight line.
Dictionary Definition
The Oxford English Dictionary defines an obtuse angle as "a plane angle: greater than 90 degrees and less than 180 degrees."Real Examples of Obtuse Angles
The angles below are all obtuse angles:
Interactive Game on the Types of Angles
Here is an interactive game to help you learn about the types of angles.
- Click on an angle so it drops into the correct "bucket."
- In total, there are 10 angles to clear.
- If an angle drops into the wrong "bucket," you will lose one of your three lives.
- Good luck!
What's in a Name?
Obtuse comes from the Latin word "obtusus" meaning "blunt". An obtuse angle makes a blunt point.Euclid and Obtuse Angles
Euclid defines angles in his book, Elements. Definition 11: "An obtuse angle is an angle greater than a right angle".Obtuse Triangles
Obtuse triangles are triangles that have an obtuse angle.
Drag and Drop Game
Here is a drag-and-drop game to help you learn about the types of angles.
This page was written by Stephen Clarke.
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