Math Problem Statement

Work out the surface area of the sphere with a diameter of 14 cm. If your answer is a decimal, give it to 1 d.p.

Solution

To find the surface area of the sphere, we will use the formula:

Surface area=4πr2\text{Surface area} = 4\pi r^2

where rr is the radius of the sphere.

Given that the diameter of the sphere is 14 cm, we can find the radius by dividing the diameter by 2:

r=142=7 cmr = \frac{14}{2} = 7 \text{ cm}

Now, substituting r=7r = 7 cm into the formula:

Surface area=4π(7)2=4π×49=196π\text{Surface area} = 4\pi (7)^2 = 4\pi \times 49 = 196\pi

Using π3.14159\pi \approx 3.14159:

Surface area196×3.14159=615.75 cm2\text{Surface area} \approx 196 \times 3.14159 = 615.75 \text{ cm}^2

Rounding to 1 decimal place, the surface area is approximately:

615.8 cm2615.8 \text{ cm}^2

Would you like more details or have any questions?

Related Questions:

  1. How would the surface area change if the diameter was doubled?
  2. What is the volume of the same sphere?
  3. How is the surface area formula for a sphere derived?
  4. What would be the surface area if the radius was given as 10 cm?
  5. How do the formulas for surface area differ for other shapes like cylinders or cones?

Tip: When working with spheres, remember that the diameter is twice the radius, so always divide by two to find the radius if only the diameter is given.

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Math Problem Analysis

Mathematical Concepts

Geometry
Spheres
Surface Area

Formulas

Surface Area of a Sphere = 4πr^2

Theorems

Surface Area Theorem for a Sphere

Suitable Grade Level

Grades 7-9