There are several geometrical definitions of a right angle: - the right angle is an adjacent corner or a corner which is equal to an adjacent corner; - a right angle is the corner which is equal 90 degrees; - measurements of corners - an and b are necessary for calculation of a right angle; - the corner of equal 90 degrees making a quarter of the whole corner and a half developed is called a right angle.
Instruction
1. These concepts and definitions indicate that one and all right angles are equal and any two corners can be comparable. And comparison of two corners with a right angle enters a concept - an acute and obtuse angle.
2. To find a right angle, it is necessary to enter measurement of degree of a corner by means of a protractor if it is equal 90 degrees, then, therefore, this angle is right.
3. A number of geometrical figures has one or several right angles. Treat such figures a rectangular triangle (has some right angles), a parallelogram (all corners its straight lines), the square is a rhombus which has all right angles and also a rectangular trapeze with one right angle.
4. It is possible to construct a right angle independently without geometrical tools with use of a plumb (any thread with cargo), level for horizontal and a glass detail for a vertical surface.