Question

By what number do you multiply the radius of a circle to double its area? Show the process to get the answer.

Answer 1

Area of circle = πr²

New doubled area = πR² ( r ≠ R )

As it is double of older area :

πR² = 2πr²

R² = 2r²

R = √2r

Thus we have to multiply the radius to √2 to double its area