If the radius of the circle is increased 3 times :
Answer: (a) 3
Let the radius of a triangle be R cm
Then, the circumference of a circle = 2 pR
If the radius of the circle is increased by 3 time.
Then, radius = 3 R
Now, new circumference of a circle = 2 x p x 3 R
= 6 pR
New circumference of a circle = 3 x 2pR (circumference of original circle)
So, the circumference of new circle will be 3 times from its original size.
Hence, the correct answer is option (a) 3.