Question

7.
If the radius of a circle is doubled, what happens to its:
(a) circumference?
(b) area?​

Answer 1

Answer:

So when you double the radius, the area goes up by 4 times because 2 squared is 4. The area will always go up by the square of how much the radius goes up. By contrast, the circumference will only double -- from 12.56 to 25.12 because you do not square the radius (or diameter) -- you just multiply it by pi

Step-by-step explanation:

Answer 2

Answer:

(a) Circumference = 2πr^2

(b) Area = πr^4

Step-by-step explanation:

Let the radius be r

(a) Circumference = 2πr

If the radius is doubled = r×r

= r^2

New circumference = 2πr^2 (Ans)

(b) Area = πr^2

New area = r×r

= r^2

= πr^4 (Ans)

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