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

2 Answers
Nov 10, 2015

Half it to find the radius and then use the formula A=pi r^2A=πr2 to find the area.

Explanation:

The formula for the area of a circle is A=pir^2A=πr2 where AA is the area and rr is the radius.

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 r=17r=17

Now we simply substitue in our value for rr into the formula.

A=pi17^2A=π172
A=289piA=289π
A=907.92mm^2A=907.92mm2 (To two decimal places)

So if you want an exact value the answer is 289pimm^2289πmm2 or if you want a decimal answer then it is 907.92mm^2907.92mm2 or 9.0792cm^29.0792cm2

Nov 10, 2015

907.9 mm^2907.9mm2

Explanation:

The area of a circle is given by the formula pir^2πr2, and the diameter is twice the radius of the circle. Knowing this, we can see that:
A=pi times(34/2)^2A=π×(342)2

and thus

A=pi times 17^2= 907.9 mm^2A=π×172=907.9mm2