approximate sag and accurate sag

[jordankane1]

Good afternoon everyone,
I kindly request some assistance with an assignment that has been set to me that is all to do with lens measures. the first question is all about sag formula.

Please see the attached picture for details.


any help is greatly appreciated as i am currently stressing out about submitting it in time.

[Don Gilman]

Good afternoon everyone,
I kindly request some assistance with an assignment that has been set to me that is all to do with lens measures. the first question is all about sag formula.

Please see the attached picture for details.




any help is greatly appreciated as i am currently stressing out about submitting it in time.

Depends on what type gauge.
There are bell gauges and ball gauges with two different size balls.

[jordankane1]

what do you mean by gauge sorry. i have completed the approximate sag column.

Any ideas on the accurate sag column?