Multiple choice

A cone-shaped paper cup has a volume of $142$ cubic centimetres and a height of $8.5$ centimetres. What is the radius, to the nearest centimetre, of the paper cup?

  1. $2$
  2. $4$
  3. $8$
  4. $12$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Volume of a cone = (1/3) * pi * r^2 * h. 142 = (1/3) * 3.14 * r^2 * 8.5. 142 = 8.9 * r^2. r^2 = 142 / 8.9 approx 15.95. r = sqrt(15.95) approx 4.

AI explanation

Use the volume of a cone formula V = (1/3) pi r^2 h and rearrange it to find the radius squared, giving r^2 = 3V / (pi h). Substitute the volume of 142 and height of 8.5 into the formula to get r^2 = (3 * 142) / (3.14 * 8.5), which is approximately 426 / 26.69. Taking the square root of 15.96 gives a radius of about 4 centimeters.

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