Math Problem Statement

The bouncy ball below is a sphere with a volume of 4200π mm³. Calculate its radius, r. If your answer is a decimal, give it to 2 d.p.

Solution

The problem provides the formula for the volume of a sphere:

V=43πr3V = \frac{4}{3} \pi r^3

We are given that the volume of the bouncy ball is 4200πmm34200\pi \, \text{mm}^3, and we need to find the radius rr, keeping the answer to 2 decimal places if necessary.

Step-by-Step Solution:

  1. The volume formula is:

V=43πr3V = \frac{4}{3} \pi r^3

  1. Substitute the given volume V=4200πmm3V = 4200 \pi \, \text{mm}^3 into the formula:

4200π=43πr34200 \pi = \frac{4}{3} \pi r^3

  1. Divide both sides by π\pi to simplify:

4200=43r34200 = \frac{4}{3} r^3

  1. Multiply both sides by 34\frac{3}{4} to isolate r3r^3:

r3=4200×34=3150r^3 = 4200 \times \frac{3}{4} = 3150

  1. Now, take the cube root of both sides to solve for rr:

r=31503r = \sqrt[3]{3150}

  1. Using a calculator to find the cube root:

r14.72mmr \approx 14.72 \, \text{mm}

Thus, the radius of the bouncy ball is approximately 14.72mm\boxed{14.72 \, \text{mm}}.

Would you like more details on any step, or do you have any other questions?

5 Related Questions:

  1. How is the volume of a cylinder different from that of a sphere?
  2. What is the formula for the surface area of a sphere, and how would you apply it here?
  3. How would the result change if the volume was given in cm3\text{cm}^3 instead of mm3\text{mm}^3?
  4. How would you solve this problem if the sphere was hollow with a certain thickness?
  5. What is the relationship between the radius and diameter of a sphere?

Tip:

When dealing with sphere-related problems, always ensure your units are consistent throughout your calculations.

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Math Problem Analysis

Mathematical Concepts

Geometry
Volume of Spheres
Algebra

Formulas

Volume of a Sphere: V = 4/3 π r³

Theorems

Volume formula for spheres

Suitable Grade Level

Grades 8-10