Amar has a square cardboard of side 4 cm. He cuts off triangular pieces from the four corners to get an eight sided regular polygon. Find the perimeter of the resultant figure?

Answer 1

Draw a figure of a regular octagon.

The hypotenuse of the cut off piece is s; therefore, the side of the original square is

2*(s/√2) + s = 4.

You should be able to get s from this equation.