For those of you who are unaware of the Los Alamos National Laboratory (possibly due to a lack of feigned-interest in the sciences), it is a very large, multidisciplinary technology and science research center in New Mexico.
The Author is telling a joke about a man who works in Los Alamos and is also not very good at science. The man is making grandiose, possibly devastating plans when it is revealed that he does not have knowledge of the most basic trigonometry (a mnemonic for remembering the properties of a triangle).
In humor, this device is called “absurdism” and can sometimes make people laugh.