So let's see what we-- oh, 155 degree angle, not 150 degree angle. Refer to the figure as you work through these steps: Draw a working line, l, with point B on it. And just to make sure that blue arc is measuring this angle right over here, not the outer one. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. (This is a proof that you can work out for yourself.) This problem is connected to what is now called the golden ratio, but its classical name is extreme and mean ratio. First, mark a point that represents the new angle’s vertex and draw a line that extends outwards from this point. And let me move the protractor out of the way so we can get a good look at it. For reference, mark the points where the arc crosses the rays as points X and Y. Use your compass to measure the distance of the arc between the lines on the original angle so you can recreate the lines on the congruent angle. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Then bisect that angle this way: Strike an arc through both rays of the angle. Extend BO to Z . Recall that an equilateral triangle has all three interior angles 60 degrees. Refer to the figure as you work through this construction: Open your compass to any radius r, and construct arc (K, r) intersecting the two sides of angle K at A and B.; Use any radius s to construct arc (A, s) and arc (B, s) that intersect each other at point Z. Ex 11.1, 4 Construct the following angles and verify by measuring them by a Protractor : 75° 75° = 60° + 15° 75° = 60° + (30°)/2 So, to we make 75° , we make 60° and then bisector of 30° Steps of construction Draw … Can you justify why this construction works? 90° Degree Angle. Please consider making a contribution to wikiHow today. Animation of how to construct a 60 Degree Angle using just a compass and a straightedge (ruler). For angles, it means they have the same angular measure. Try an example. Therefore, this construction focuses only on a single congruent angle, but in fact you will create a congruent triangle (if you connect points XY and points FG). Amid the current public health and economic crises, when the world is shifting dramatically and we are all learning and adapting to changes in daily life, people need wikiHow more than ever. figure shows angle of 160° drawn by compass. Then using a compass, we use this as a base to construct an equilateral triangle. A Euclidean construction. Thanks to all authors for creating a page that has been read 100,944 times. To construct a 60° angle, we first draw a line of any length. If the copied angle does not appear to be exactly congruent to the original, you should check that your compass remained stable each time that you lifted it off the paper. To create a 45-degree angle, you need to bisect . Let me fix that. An angle trisectionis a construction that takes an angle and creates an angle that has a measure of 1/3 of t… We use cookies to make wikiHow great. 7). Construct 90 Degrees angle | Also see How to draw angles 30 45 60 90 degrees with Compass. Nov 2, 2013 - On this page we show how to construct (draw) a 90 degree angle with compass and straightedge or ruler. wikiHow's Content Management Team carefully monitors the work from our editorial staff to ensure that each article is backed by trusted research and meets our high quality standards. See the proof below for more details. I.e., 15°, 30°, 45°, 90°, ..... . How to Construct an Angle Congruent to a Given Angle. This video shows how to construct a 60 degree angle with the help of ruler and compass only. If two angles are congruent, it means their angles are equal to one another, so drawing a congruent angle involves replicating a given angle. Mark is the author of Calculus For Dummies, Calculus Workbook For Dummies, and Geometry Workbook For Dummies. How to construct a 90° degree angle using just a compass and a straightedge Label as C the point of intersection of the arcs. Learn about topics such as How to Construct a 30 Degrees Angle Using Compass and Straightedge, How to Construct a 60 Degrees Angle Using Compass and Ruler, How to Construct a Line Parallel to a Given Line Through a Given Point, and more with our helpful step-by … Using the same compass width, place your compass point at F and draw an arc in the interior of . {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/7\/79\/Construct-an-Angle-Congruent-to-a-Given-Angle-Step-1-Version-2.jpg\/v4-460px-Construct-an-Angle-Congruent-to-a-Given-Angle-Step-1-Version-2.jpg","bigUrl":"\/images\/thumb\/7\/79\/Construct-an-Angle-Congruent-to-a-Given-Angle-Step-1-Version-2.jpg\/aid2560770-v4-728px-Construct-an-Angle-Congruent-to-a-Given-Angle-Step-1-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"