We measure it in an anti-clockwise manner by using a protractor in a degree. We make use of the symbol ∠ to denote an angle. Solution: α = 90° + 45° = 135° and β = 180°.Īnswer: An angle is formed by two lines or line segments or rays with a common point. Problem: What is the value of angles α, β? Question 1: Name the angle when the time in a clock is 3: 40 pm? Is it Obtuse or Reflex or Acute Angle?Īnswer: The angle is measured in an anti-clockwise manner and thus the angle formed is reflex and not obtuse or acute angle. Even we make different angles in different postures while doing yoga and exercises. What is the angle in letter V? An acute angle. Different alphabets also form the examples of angles. Where else can we find angles?Ĭloth-hangers, scissors, arrowhead, partly opened-doors, pyramids, Set squares, an edge of a ruler, an edge of tables, cycle spokes, wheels etc are examples of angles in real life. In direction, we can find various angles. What is the angle made by both hands of the clock? It is a right angle. Consider an example, the clock shows the time is 3 o’clock in the morning. In the beginning, we have talked about angles formed by the hands of a clock. are equal in measurement. Here, ∠1 = ∠2 and ∠3 = ∠4. The pairs of the opposite angles are vertically opposite angles (V.O.A).

Vertically Opposite Angles: Suppose two straight lines AB and CD intersect each other at a point O.

Supplementary Angles: When the sum of a pair of adjacent angles is 180°, the angles are supplementary angles.

Complementary Angles: Two angles are complementary to each other if the sum of both the adjacent angles is 90°.

Is there any other pair of adjacent angles? ∠AOC and ∠COB, and ∠AOB and ∠AOC are another sets of adjacent angles.

Adjacent Angles: Two angles are adjacent if both of them have one common arm and a common vertex. ∠AOB and ∠COB are the adjacent angles.

Other Type of AnglesĪpart from the above-mentioned angles, there are other types of angles too.

This angle is formed as the arm makes one completes turn and returns to its starting position. If the measure of an angle is 360°, it is a complete angle. Reflex AngleĪ reflex angle is the one that is greater than 180° and less than 360°. This angle got its name as it forms a straight line. ∠AOB is a straight angle. Straight AngleĪn angle whose measure is 180° is a straight angle. Acute AngleĪn acute angle is the one that is greater than 0° and less than 90°.Īny angle whose measure is equal to 90° is a right angle.Īn angle is said to be an obtuse angle if it is greater than 90° but is less than 120°. The initial and the final arms are at the same position. ∠AOB is zero angle. Based on the degree of measurement, the angles are classified as: Zero AngleĪn angle whose measure is 0° is zero angle. There are different types of angles formed by two lines or rays with one common starting point. The other arm shows the degree of the angle when measured from the initial arm in an anti-clockwise manner.

Measuring Angle: Place the center of the protector at the fixed point, say O of the angle at one of the arm.They are also called the sides of the angle. Arms: The two rays forming an angle from a fixed point are arms.Vertex: The common starting point in an angle is a vertex.An angle is measured in an anti-clockwise manner with the help of a protector in degree. Two lines or line segments or rays with a common point form an angle. An angle is denoted by a symbol ∠. Browse more Topics under Shapes And Angles Are the two angles same every time? Maybe it is not. What will you find? Two lines and a common point O. For sun rays, the Sun is the fixed point and thus we say the light coming as sun rays.ĭraw one more point other than O and P and call it R. It cannot go in both the direction like that a line. Have you ever thought why we say sun rays and not sun line? Is ray different from a line? Yes, it is. Do you know a line has no endpoints like line segment? A line has many line segments in it.

What did you get? A line segment OP with endpoints O and P. How many did you get?ĭraw another dot and name it P. From this point draw as many straight lines as you can. Take a piece of paper and drawn a dot anywhere on it. Before studying angle, let us do one interesting thing.

Supplementary angle in real life