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Geometry - Learn About Angles TutorGiant When we measure angles, we use ‘degrees’ which are units of measurement. An angle is formed when two lines or two rays (a ray is a point that extends into a line) meet. The symbol for angle is ‘<’. The place where two lines meet in an angle is called the vertex. When we name an angle, we use the point of the vertex as the middle letter. Sometimes, we can refer to an angle as just one letter. When measuring angles, we must line up one of the lines along the flat edge of the protractor, then extend the other line with a ruler if it isn’t long enough and record where it ends on the protractor. Facts about angles: · An angle less than 90° is called an acute angle. · An angle that is greater than 90° and less than 180° is called an obtuse angle. Join Now for ONLY $9.95 Click to Join for a Lifetime Membership · An angle that is exactly 90° is called a right angle. · Angles cannot have negative measures. · When two lines intersect, they form four angles which are considered vertical angles. · When two angles add up to 180° they are supplementary. · When two angles add up to exactly 90° they are complementary. We can identify a right angle by a little square that is placed inside the vertex of the angle. Right angles look like the letter ‘L’. This ‘L’ shape can be upside down, backwards, or on an angle. When an angle is bisected it means that it is split into two exactly equal parts. We can also classify triangles based on their angle measures. For example, a right-angled triangle has one right angle. An obtuse-angled triangle has one obtuse angle. Finally, an acute-angled triangle has only acute angles. The basic understanding of the angle concepts will improve a student’s geometry skills. ©Tutorgiant.com
Tutorgiant.com provides Angle lessons with worksheets. See some of the lessons in our video library.
Learn'Em Good Math by Stuart Ackerman MSc.Ed.,B.A. |
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