(1)$\phi =\mu -40\mathrm{°}\backslash ;\backslash ;\backslash ;\backslash varphi\; =\backslash mu\; -\; 40°\backslash ;\backslash ;$ (Textangabe)

(2)$\mu =2\cdot \phi \backslash ;\backslash ;\backslash ;\backslash mu\; =\; 2\backslash cdot\backslash varphi\backslash ;\backslash ;\backslash ;\backslash ;$ (Randwinkelsatz)

(2) in (1) eingesetzt:

$\phi =2\phi -40\mathrm{°}\mathrm{\mid }-\phi +40\mathrm{°}\backslash varphi\; =\; 2\backslash varphi-40°\backslash ;\backslash ;\backslash ;|-\backslash varphi+40°$

$\phi =40\mathrm{°}\backslash varphi=40°$

$\mu =80\mathrm{°}\backslash mu=80°$