How to draw an angle without a protractor

Draw one side of the corner. To do this, first select the point which should be its top, and mark the letter A. Guide starting from her line - side corner.

Construct an auxiliary line perpendicular to the side. On graph paper it's easy to do, and unruled paper and in the absence of a square you can use a compass. This method is useful for cases when on the graph paper side of the corner angled. Draw two intersecting circle, the centers of which lie on the side of the angle. Guide line through the intersection points of the circles it will be perpendicular. The point of intersection with the side of the angle mark with the letter V.

Measure the length of the segment AB. The resulting number will participate in the calculations, therefore, desirable to construct a perpendicular at that distance from point A to number was round - this will simplify calculations.

Put on the perpendicular distance which is equal to the product obtained in the previous step number by the tangent of the desired angle. To compute the tangent of, use tables of trigonometric functions or a calculator, for example integrated in the operating system software calculator. For example, if the length AB is 20 cm, and draw the necessary angle of 55°, the perpendicular should be postponed 20*tg(55°)≈20*tg(55°)≈20*1,428=28,56 see

Instead of the tangent, you can use another trigonometric function - for example, if you choose the cosine, the length of line AB should be divided by the cosine of the desired angle. But in this case you get the length of the second side of the angle, and the point of its adjacency to the perpendicular should be determined with the help of a compass. For example, from the previous step of the calculation in this case would look like this: 20/cos(55°)≈20/0,576≈34,72 see the resulting value is put on the compass, set it to the vertex of the angle and mark off on the perpendicular point of intersection with the imaginary circumference of pending radius.

Off on the perpendicular one of the described methods cut the desired length, put a dot and label it with the letter C. Then draw the second side of the corner connect the top (point A) from point C. In this construction the corner YOU will have completed.