An equilateral triangle has all the sides that equal the included angles are also equal.

These are some important concept on the Geometry that can help to solve the problems in Co-ordinate geometry

For a given perimeter the equilateral triangle has the largest area

For a given area the equilateral triangle has the least perimeter

- Area (A) of Equilateral triangle is = A = [ (square of a Side) x Square root of 3 ] / 4 =
- Remember all the sides of equilateral triangle are equal

- Perimeter of Equilateral triangle = 3s – S is the side of triangle
- The radius of the circumscribed circle (the circle touching all the vertex from outside) = R = s x (Square root of 3)/ 3
- The radius of the inscribed circle – r = s x (square root of 3) / 6
- Height of the equilateral triangle = h = s x (square root of 3)/ 2
- For any point P in the plane, with distances
*p*,*q*, and*t*from the vertices A, B, and C respectively , s is the side of triangle

3(*p*^{4} + *q*^{4} + *t*^{4} + *s*^{4}) = (*p*^{2} + *q*^{2} + *t*^{2} + *s*^{2})^{2}.

- For any interior point P in an equilateral triangle, with distances
*d*,*e*, and*f*from the sides,*d+e+f*= H , the altitude of the triangle, independent of the location of P - For any point P on the inscribed circle of an equilateral triangle, with distances
*p*,*q*, and*t*from the vertices, s is the side of triangle

16(*p*^{4} + *q*^{4} + *t*^{4}) = 11*s*^{4 and }4(*p*^{2} + *q*^{2} + *t*^{2}) = 5*s*^{2}

- For any point P on the minor arc BC of the circumcircle, with distances p, q, and t from A, B, and C respectively, p = q + t and
*q*^{2}+*q**t*+*t*^{2}=*a*^{2}

- If point N on side BC divides PA into segments PD and DA with DA having length
*z*and PD having length*y*, thenwhich also equals if

*t*≠*q*; andIf you liked my contribution, please donate or click on any of advt. a little that will be generated will all be donated for noble cause. [paypal-donation]