Fundamentals of Math

Fundamentals of Mathematics

Obtuse Angles

Straight Angles

When lines come together to form an enclosed shape (with multiple angles), we define this as a polygon . Let's look at some specific polygons and their properties.

5.1 Properties of Triangles Triangles are any plane figure with three straight sides and three angles. The sum of the interior angles of any triangle will always sum to 180 degrees. Despite this fact, triangles come in a variety of shapes and sizes. The different types of triangles are classified by the size of their angles or their side lengths.

Recall acute angles (measures less than 90° ), right angles (measures precisely 90° ), obtuse angles (measures more than 90° ), and straight angles (measures precisely 180° ). The same angle classification carries over to types of triangles: acute, obtuse, right.

Acute Triangle

Obtuse Triangle

Right Triangle

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