In the adjacent figure ABCD is a square and `Delta APB` is an equilateral triangle. Prove that` DeltaAPD ~= DeltaBPC`.

In the adjoining figure , Delta PQR is an equilateral triangle. QR = RN . Prove that PN^(2) =3PR^(2)

In the adjacent figure, Delta ABC is right angled at C and DE bot AB . Prove that Delta ABC ~ Delta ADE and hence find the lengths of AE and DE ?

If in a Delta ABC, cosA+ cosB + cosc =3/2. Prove that DeltaABC is an equilateral triangle.

Show that the angles of an equilateral triangle are 60^@ each.

in the adjoining figure, Delta PQR is an equilateral triangle. Point S is on seg QR such that QS = 1/3 QR , Prove that 9 PS^(2) = 7 PQ^(2)

Find the height of an equilateral triangle having side 2a. (i) Delta ABC is an equilateral triangle. AB = 2a

The perimeter of an equilateral triangle is 30 cm. The area is

All equilateral triangles are ...............