What was the "oxygen revolution," which took place 2. 3 billion years ago?.

Short summary:

The "oxygen revolution" was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, with the origin of plants, immediately preceding the origin of animals.

answer: this problem has only trivial solutions, with all points on the same line. x=5 or x=7/5.

step-by-step explanation:

there are three triangles, and three unknowns: x, y=length of middle segment, and z=cos(angles marked with red arc).

we need

and law of cosines,

the three equations are

see attached image for solution.

i really really really really really really dont know