To draw on paper the main geometrical figures - such as rectangle, circle, rhombus or, in this case, isosceles triangle, it will be simple by means of compasses and a ruler. To be able to carry out such construction each school student of middle school has to.

## It is required to you

- - pencil;
- - compasses;
- - ruler;

## Instruction

1. Draw on the sheet of paper a piece by means of a pencil and a ruler. Note the ends of a piece points And yes Century. This piece will be the basis of your isosceles triangle. Draw it in the middle of a leaf or the middle - are slightly lower so that future triangle was located on a leaf. Do not do a piece too long, especially in all width of a leaf - so at you construction details will not be located. Take AV piece size approximately in a quarter of width of the sheet of paper.

2. Establish a leg tsikrulya in a point And yes carry out a circle. You can take the radius of this circle any, but it has to be not less than a half of length of a piece of AV. Slightly more piece of AV that the triangle with guarantee turned out acute will be convenient to take circle radius. Keeping the same radius, draw a circle with the center in a point of Century. These circles have to be crossed in two points, note these points as C and D. If the radius of circles was chosen by you as insufficient, two circles will not be crossed. In this case, increase radius as above in this point is told.

3. By means of a ruler connect pieces of a point And yes With and also points In and Page. From three nacherchenny pieces at you the triangle of AVS which is isosceles as its parties and the EXPERT are equal to VS each other turned out. It is easy to prove it - we will put that the radius of circles with the centers in points And yes In equaled R. In this case distance the EXPERT = R as C lies on R radius circle with the center in a point And. As well VS = R as C lies on R radius circle with the center in a point of Century. Thus, VS = the EXPERT = R, that is two parties of a triangle are equal each other, as was to be shown.