Multiple choice

When the circumference and area of a circle are numerically equal, find the numerical value of its diameter.

  1. $\dfrac{\pi}{2}$
  2. $8$
  3. $2 \pi$
  4. $4$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Circumference = 2 * pi * r. Area = pi * r^2. Setting them equal: 2 * pi * r = pi * r^2. Dividing by pi * r (assuming r is not 0), we get 2 = r. The diameter is 2 * r = 4.

AI explanation

Setting the circumference and area formulas equal gives 2 times pi times r equals pi times r squared. Dividing both sides by pi times r leaves r equal to 2. The diameter is twice the radius, so the diameter is 4.

Keep practicing — related questions