A semicircular piece of paper (with radius 7 cm) is folded along the diameter to form a cone such that he centre of the semicircle becomes the vertex of the cone.If the base of the cone is covered by a circular paper lid, what is the total surface area of the cone ?

What is the minimum length of a string with which one can surround a triangle of area 36√3 cm?

If shortest side of a right angled triangle was 5 cm longer and the longest side was 5 cm shorter, the triangle would be equilateral.  What is the area of the original right angled triangle?