# What is the area of a circle with diameter 34mm?

##### 2 Answers

Half it to find the radius and then use the formula

#### Explanation:

The formula for the area of a circle is

Since we only know the diameter we need to figure out the radius. Since the radius is always half the diameter we now know that the radius is 17mm and that means we know that

Now we simply substitue in our value for

So if you want an exact value the answer is

#### Explanation:

The area of a circle is given by the formula

and thus