Instruction

1

Method 1. Classic.

Area of isosceles triangle can be calculated by the classic formula: polypropelene the base of the triangle to its height.

S=1/2bh

b is the length of the base of the triangle;

h - the length of the height of treugolnika.

Area of isosceles triangle can be calculated by the classic formula: polypropelene the base of the triangle to its height.

S=1/2bh

b is the length of the base of the triangle;

h - the length of the height of treugolnika.

2

Method 2. Heron's Formula.

a - length one of the equal sides of the triangle;

b - length of base of triangle.

a - length one of the equal sides of the triangle;

b - length of base of triangle.

3

Method 3. It follows from the formula of method 1.

α is the angle between the side and the base;

γ - the angle between the equal sides.

α is the angle between the side and the base;

γ - the angle between the equal sides.

Note

There are signs of an isosceles triangle:

1) an isosceles triangle has 2 equal angles;

2) the height of the triangle coincides with its median;

3) the Height of a triangle coincides with its bisector;

4) angle Bisector of a triangle coincides with its median;

5) the isosceles triangle the median is equal to 2;

6) isosceles triangle 2 equal height;

7) an isosceles triangle 2 equal bisectors.

1) an isosceles triangle has 2 equal angles;

2) the height of the triangle coincides with its median;

3) the Height of a triangle coincides with its bisector;

4) angle Bisector of a triangle coincides with its median;

5) the isosceles triangle the median is equal to 2;

6) isosceles triangle 2 equal height;

7) an isosceles triangle 2 equal bisectors.