Trigonometric Functions: Background You’ll Need 4

  • Find the area and circumference of a circle

area and circumference of a circle

A circle has two key measurements you’ll often need to find:

  • The circumference is the distance around the circle. The formula for circumference is [latex]C = 2\pi r \quad \text{or} \quad C = \pi d[/latex]

  • The area (A) is the space inside the circle. The formula for area is [latex]A = \pi r^2[/latex]

where [latex]r[/latex] is the radius and [latex]d[/latex] is the diameter of the circle.

Find the circumference and area of a circle with radius [latex]6[/latex] meters.

Although calculators have a [latex]\pi[/latex] button, it’s best to complete the calculations on your calculator without [latex]\pi[/latex] and then writing [latex]\pi[/latex] at the end to give an exact answer in terms of [latex]\pi[/latex].