Prove that the area of an equilateral triangle described on one side of a right angled isosceles triangle is half the area of equilateral triangle described on its hypotenuse.
Refer the following link for the answer similar to your query:
https://www.meritnation.com/ask-answer/question/prove-that-the-area-of-an-equilateral-triangle-described-on/triangles/6295453
https://www.meritnation.com/ask-answer/question/prove-that-the-area-of-an-equilateral-triangle-described-on/triangles/6295453