Right angles are indicated with grey squares. The solution can be expressed as a fraction.

Good luck!
Previous iteration: #731084 (the solution was indeed Euler's constant e, see #731144).
I will probably be slightly less regular this week in posting the puzzles, busy week ahead.
The small triangle at the bottom right must be right and isosceles, and the angle at the bottom right must be 45°, because the sum of angles is 180°.
This means the largest triangle is isosceles, and the bottom length is 4, i.e. the units are 21.
We begin with z2+z2=1 giving z2=21
The we continue to the left, looking at the small triangle with sides y, c, and 1:
Similarly we continue for x and w and get
The last two x2 should be y2. Is there a way to edit after 10 minutes?
Can't edit after 10 minutes. Not sure the reason is technical or ideological.
1/( (4/5)^2 ) + 1/( (4/3)^2 ) + 1/( (4/2)^2 ) + 1/( (2√2)^2 ) = 5/2