The lateral faces of a square pyramid are equilateral triangles of side 30 cm. What is the surface area?

Construct an equilateral traingle of side 5.5cm.

Draw an equilateral triangle whose sides are 5.2 cm. each

Prove that the ratio of the area of a circle and the equilateral triangle whose side is equal to the diameter of the circle is pi:sqrt3

ABC is an equilateral triangle of side 2a. Find each of its altitudes.

The area of an equilateral triangle ABC is 17320.5 cm^2 . With each vertex of the trianlge as centre, a circle is drawn with radius equal to half the length of the side of the triangle. Find the area of the shaded region .

Derive the formula for height and area of an equilateral triangle.

The altitude of an equilateral triangle having the length of its side 12 cm is

Find the area of the shaded region in Fig. 5.22, where a circular arc of radius 6 cm has been drawn with vertex O of an equilateral triangle OAB of side 12 cm as centre.

Find the perimeter of each of the following shapes: (b) An equilateral triangle of side 9 cm.

Three coins of unit radius are placed in an equilateral triangle as shown in the following figure. The area of that equilateral triangle is :