Surface area of a sphere worksheets

The surface area of a sphere is 4πr², and at π = 3.14 that is 12.56 times the radius squared. These free printable worksheets label some figures with a radius and some with a diameter, so the first step is always reading which one you were given.

Surface area of a sphere
Surface area of a sphere worksheet — Radius or diameter, π = 3.14, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

The mistake that costs the most marks is not the formula, it is the label. A sphere 18 cm across has a radius of 9, and squaring 18 instead gives an answer four times too big. Circling the word radius or diameter before touching a calculator is a habit worth more than any amount of extra practice on the multiplication itself.

Why this sheet works

Squaring is the other half, and it is smaller trouble here than on the volume sheet: r² means r × r, not r × 2. Working the square out on its own line before multiplying keeps the two steps from running together. Then it is one multiplication — 4 × 3.14 is 12.56 every time, which a child who notices it only has to work out once for the whole page.