Solving gradients of right angle triangle

[mamort]

Please take a look at attached diagram displaying gradients of each line, please explain how m3 is obtained.

 

[Mentallic]

No. If you don't specify how long the arms of the short sides of the right triangle need to be, then you can make m₃ be whatever you want, and you'll still have a right-triangle with 1/x and -x as the gradient of two of the sides.

 

[mamort]

True I think I might of head down the wrong path I am trying to solve the following problem in the diagram below. I am unsure how u1 is obtained. I assume that the gradient of the green line is used to solve as shown below

m3 = (hz+delta_hz)/(u1)
therefore
u1 = (hz+delta_hz)/m3
where
m3 = 1/k3+k3

If this is the case then how has m3 = 1/k3 + k3 been calculated?
Otherwise can you please explain how u1 has been obtained?