"Direct" call the corner having the size in 90 ° that corresponds to a half of number of Pi in radians. It makes a half of size of the developed corner which coincides with a straight line - this fact is used for determination of perpendicularity of two straight lines. With use of right angles many correct geometrical figures which form the majority of the objects and constructions created by the person has are under construction.
It is required to you
- Paper, compasses, protractor, ruler, pencil.
Instruction
1. If the lines forming a corner, nacherchena on paper then to define that the corner is to straight lines it is possible, for example, by means of a protractor. Apply it parallel to any of the parties so that the zero mark coincided with vertex of angle. If other side of angle corresponds to ninety-degree division of a protractor, then you can be congratulated - you defined that this angle and is right. Same most it is possible to do also by means of the square and if absolute accuracy is not required, then even with use of other disposed objects - a matchbox, a diskette, a plastic box CD DVD disk and any other rectangular subject.
2. If in statements of the problem lengths of the parties of a triangle are given, then you should define that from them which is a hypotenuse - the angle lying opposite to it will be right. The hypotenuse is always the longest party of a rectangular triangle therefore with preliminary definition its problems will not be. If such there are two, then the triangle is not rectangular and there is no corner necessary to you in it at all. Otherwise make additional check - the square of length of a hypotenuse has to be equal to the sum of squares of lengths of two short parties (legs). If this is so, then the angle lying opposite to the long party (it is usually designated by a letter γ) is right.
3. If you need to calculate creation of a right angle, then do operation, the return described in the previous step. At first determine lengths of two parties which will form this corner. It is simpler to work with the correct isosceles triangle therefore it is better to take identical lengths of legs. If the result has to be displayed on paper, then postpone the necessary length on compasses, put the end to top of future corner and designate it by letter A. Draw a circle with the center in this point and carry out radius, having designated a point of its contact with a circle with letter B. Then calculate hypotenuse length - increase leg length by a square root from the two. Postpone the received value on compasses and draw the second circle with the center in a point V. Zatem connect a point of intersection of two circles (a point C) to the center of the first circle (a point A). It will also be a right angle YOU.