An angle smaller than a right angle is called an acute angle, an angle greater than right angle but less then straight angle is obtuse angle while a reflex angle is larger then a straight angle. I this chapter we will also learn how to categorize triangles based on the angles that it has.
One complete revolution is divided into 360 equal parts. Each part is a degree, and angles are measured in degrees. A right angle is 90 degrees and a straight angle is 180 degrees. In this topic we will learn how to measure angles in degrees. We will also learn how to use a protractor and to solve for unknown angles.
Not all things with four sides and 90 degree angles are squares or rectangles! Sometimes the angles in these 4-sided shapes are less than (or greater than) 90 degrees, causing them to have a slightly odd shape. These are called quadrilaterals and come in a few different varieties. In this tutorial, you'll learn about them.