Answer: 7.29π mm²
Explanation:
First, I am assuming XY is the diameter of the circle :)
The formula for the area of a circle is πr² (r = radius)
So that means we need to divide the diameter by 2 to find the radius
5.4 / 2 = 2.7
Now we simply plug in our numbers!
3.14 · 2.7²
3.14 · 7.29
And that's it!
Hope this helped you :)