Answer:
let the equal sides of the triangle be of length "a" . let the angle between these two sides be " x ". Then drop a perpendicular from the vertex to the base. now u have 2 similar triangles .the angle between the perpendicular and one of the equal sides is now (x/2) . length of perpendicular = a cos(x/2) length of base = 2a sin(x/2) . area of triangle = (1/2) 2sin(x/2) cos(x/2) a-square
= (1/2) (sin x) a-square
