Use the arc that allows you to measure an angle in the direction you prefer: clockwise or counter/anticlockwise. The difference angle will still be ∠SPQ as before. An obtuse angle: Obtuse angles ALWAYS measure more than 90 degrees, but less than 180 degrees. Next, measure the length of the adjacent side to find the run. How do I know which arc to use when measuring any angles? about 90° more than 180°. You may find it easier to measure if you turn your paper so that the acute angle is facing straight up. To measure an acute angle without a protractor, start by drawing a vertical line connecting the 2 rays of the angle to form a right triangle. No matter how wide, the direction the alligator is pointing when its "jaws" are closed is the direction the angle opens. Solution: True. If there is no straight line, there's no angle to measure. Kyla thinks it is about 110°. Her dance teacher may call it an obtuse angle. In the daily learning life, we often need to draw angle and the most commonly used is the triangle belts of 30 °, 45 ° and 60 °. Apaper, a ruler and coloured pens. Some simple math could give us the answer. In the drawing process, the frequency of drawing vertical line and right angle is very high. When you have this number, you can calculate the degrees of your acute angle by typing the value for slope into a scientific calculator. Mark right angles, angles more than a right angle and angles less than a right angle with different colours. In some diagrams, you may see more than one angle. Knowledge of a right angle. So, for example-- let me do this in a color I haven't used-- an angle that looks like this, and let me draw it a little bit better than that. An angle measures the amount of turn. Protractors usually provide numbers in 10s. The arc around the vertex shows you which angle you're supposed to find the value of. [1] I need you (community) to verify it. A right angle is exactly 90 degrees. An angle whose measure is more than 180° and less than 360° is called a (a) Reflex angle (b) Acute angle (c) Straight angle (d) Complete angle (a) Reflex angle. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Tip: If you get confused because the angle is upside down, turn your paper and ignore the reflex angle until the last step. In these worksheets, students classify angles as straight, right, acute or obtuse. To make sure you're right on the vertex, it can help to make a little dot inside the center of your protractor. Hold a ruler level, then slope the ruler to an angle of 45 degrees. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Start by drawing a horizontal line and marking the left end “A” and the right end “B” to serve as the vertex of the angle. An obtuse angle is more than 90° and less than 180°. Acute angles ALWAYS measure less than 90 degrees. Drawing an angle using a protractor is very simple. However , not all the angles we come across are one of these two kinds. To continue the example, if the smaller acute angle measures 26.565 degrees, the reflex angle would measure 333.435 degrees. But, does that mean the school ruler is the right choice? Variation: There are full-circle protractors that eliminate the need for this additional math. 39 (1966), 239-241. Otherwise, if your angle opens to the right, use the number in the inner arc. Include your email address to get a message when this question is answered. These angles are acute angles, which means they are less than a right angle (less than 90°). {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/8\/83\/Measure-an-Angle-Using-a-Protractor-Step-1-Version-2.jpg\/v4-460px-Measure-an-Angle-Using-a-Protractor-Step-1-Version-2.jpg","bigUrl":"\/images\/thumb\/8\/83\/Measure-an-Angle-Using-a-Protractor-Step-1-Version-2.jpg\/aid6897726-v4-728px-Measure-an-Angle-Using-a-Protractor-Step-1-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"