Can anyone explain how to do it for me? i don't understand...

15[m].

Explanation:

1) the required distance is AD, for more info see the attached picture.

2)

“other instruments such as gravimeters and magnetometers are also used in the search for petroleum. extracting crude oil normally starts with drilling wells into an underground reservoir. when an oil well has been tapped, a geologist (known on the rig as the "mudlogger") will note its presence. “ this is what i found on google i hope it

So what is the question