Two angles are said to be supplementary if their sum is 180 o. Are supplementary angles Straight angles? What do you observe? The base of the stairs makes an angle of 180 o and hence forms a straight angle. Observe the angle made by the base of the stairs below – Have you ever observed the angle made by a see saw when it is at a balanced position? Both the ends of a see saw make an angle of 180 o when they are in alignment with each other. Have you ever noticed the different angles made by the hands of a clock at different times? Check the time shown by the clock below?Ĭan you notice the angle made by the hands of a clock when it reads 6:00 pm. There are many instances in real life where we make use of straight angles. Thus we get our straight angle in the form of AOB.
The second ray OB will have the arrowhead at B. In the last step we join the vertex of the line OA with the point B.On arriving at 180°, we mark a point B on the paper. In the next steps, we start from 0° and move towards 180° marking of the protractor.It is important to note here that the A should be pointing towards the 0°of the protractor. Now we keep the protractor on this line such that the baseline of the protractor is aligned over OA.The first steps towards drawing a straight angle using a protractor are to draw a straight-line OA, with an arrowhead at A.So, what are the steps that we follow to draw or locate a straight angle using a protractor? The following are the steps required – This is where drawing or locating a straight angle becomes easier and accurate when one uses a protractor.
#Supplementary angle in real life how to#
How to Draw a Straight angle using a Protractor?Īlthough a straight angle can be drawn by just drawing a straight line, there are at times, when you need to measure and locate straight angles, especially when it comes to complex diagrams. When we move clockwise the straight angle measures – 180 0.When we move anticlockwise the straight angle measures + 180 0.A straight angle is formed by rotating one ray by 180° with respect to another ray.The arms of a straight angle are always extending in opposite directions.Two right angles can be joined together to form a straight angle.A straight angle modifies the direction of a point.therefore, half of the revolution, which is 180 o is the measure of a straight angle. We know that the measure of one revolution is equal to360 o. The measure of a straight angle is always exactly half of a revolution.The following are the properties of straight angles In degrees, the straight angle is represented as 180° and in radians it is denoted with pi (π). We now know that whenever two rays join together they form an angle and the angle subtended by two rays in opposite directions is called a straight angle. Hence, a pair of straight angles could have been formed if we increased the second angle by 2 o. We already know that for a pair of angles to form a straight angle the sum of the angles is equal to 180 o. What changes could we have made in the other angle if we kept the first angle as 125° and the pair formed a straight angle? Let us check. Hence, the two given angles, 125° and 53° cannot form a straight angle. We can see that the sum of the two given angles does not equal 180 o Hence, let us check the sum of the two given angles. Therefore, for the given two angles to form a pair of straight angles, their sum has to be equal to 180 o.
We have learned that a straight angle is formed when the sum of the angles is equal to 180 o. The following is the description of a straight angle –Ĭheck whether the angles 125° and 53° can form a straight angle. Since a straight angle is 180 degrees, half of it will be 90 degrees which is a right angle. It is important to note here that half of a straight angle is a right angle. Straight angles are sometimes also referred to as flat angles. The arms of a straight angle lie on the opposite side of the vertex. In other words, a straight angle is an angle that forms a straight line. DefinitionĪ straight angle is an angle, whose vertex point has a value of 180 degrees. One of such angles is a straight angle? What is it and how is it formed? Let us learn more about it. artists use their knowledge of angles to sketch portraits and paintings. Engineers and architects use it for designing roads buildings etc.
Knowledge of angles is made use of in many spheres of everyday life. We know that an angle is a portion of the plane between two rays that are joined by a vertex.