The correct triangle call a triangle with three equal parties. It has the following properties: all parties of the correct triangle are equal among themselves, and all corners are equal to 60 degrees. The correct triangle is isosceles.
It is required to you
- Knowledge of geometry.
Instruction
1. Let the party of the correct triangle with a=7 length be given. Knowing the party of such triangle it is possible to calculate its area easily. The following formula is for this purpose used: S = (3^(1/2) *a^2)/4. Let's substitute in it a formula value and =7 and we will receive the following: S = (7*7*3^1/2)/4 = 49 * 1.7/4 = 20.82. Thus received that the area of an equilateral triangle with the party and =7 is equal to S=20.82.
2. If the radius enteredof in a triangle of a circle is given, then area formula through radius will look as follows: S = 3*3^(1/2) *r^2 where r is the radius of an inscribed circle. Let radius of an inscribed circle of r=4. Let's set up him in the formula written earlier and we will receive the following expression: S = 3*1.7*4*4 = 81.6. That is at the radius of an inscribed circle equal 4th Square of an equilateral triangle will be equal to 81.6.
3. At the known radius of a circumscribed circle the formula of the area of a triangle looks so: S = 3*3^(1/2)*R^2/4 where R is the radius of a circumscribed circle. Let's say that R=5, we will substitute this value in a formula: S = 3*1.7*25/4 = 31.9. It turns out that at the radius of a circumscribed circle equal 5th Square of a triangle is equal to 31.9.