Your profile says Ruida, but you do not identify the wattage of the Laser, so it is hard to offer direct answers. Here is a post talking about cutting acrylics.
Here is another post to the Boss Laser site where they offer cut setting suggestions for a bunch of different materials using different powered systems:
Ruida 100 w laser
Are the cut settings wrong?
Wrong? This is hard for me to tell from here as I can not see how this is processing. Air assist, power and the speed you are traveling, are all important variables you will need to test to find the best setting for the task. Test, test, and then test some more. Each laser will produce the job slightly differently and the only way to find the correct settings for your machine is to do the testing on your system directly.
Google and YouTube are your friends for researching consistent cut testing procedures to produce what you want. Without the details, I can not offer much more.
hi rick
cut settings as seen in the picture
the first problem did not cut 3mm spartan oak
The second problem is why it is not a full circle even though the dimensions are the same.
Change the Min Power value to match the Max Power value:
When moving very slowly (10mm/sec or less, usually, but sometimes more) the controller ONLY uses the Min Power setting, so you’re only running at 20% power for this cut.
Some additional on the subject to help with understanding:
thank you
The second problem is why it is not a full circle even though the dimensions are the same.
does it have anything to do with it
Please explain and show us what this means, please.
You are currently showing, highlighted in blue, the bed size you have set in this Device Profile. This is where you tell LightBurn the physical size of your hardware, so not understanding why you are sharing this information. 
ok i send picture
How does this file look in the ‘Preview’ window? Do you notice this elongation along the X axis when running other files? You could try cutting a simple circle to test against. 
i tried, same problem, circle is not round
Is this the controller that came with this laser, or a replacement controller / home-built setup? I ask because if true, I am now thinking you may be having a ‘Step Length’ issue requiring calibration. If this is a factory installed controller, you may need their original settings file or revert to their suggested settings manually to resolve.
Provide an update when you can and we can go from there.
Wait, Preview shows this elongated?
And the simple circle test produced the same in Preview and a test run on the laser?
Please post this LightBurn file for our review.
If you draw a perfect square or circle, are they coming out perfect in the preview, but not on the machine? If so, then it’s likely to be one of two things:
You can calibrate in Edit > Machine Settings. You run a job of a known size, like 10" or 200mm or something (the size doesn’t matter, but larger is better). Then you tell the Axis Calibration tool how large you asked for and how large you got, and it will correct the machine step size to compensate for it.
I did the same for the x and y axes and it was fixed
thanyou so much
Glad to hear you have this sorted.
