Răspuns :
notez cu α masura unghiurilor BOM≡MOC si cu β masura ung. AOP≡POD
x=masura <BOD
<COD=90=2*α+x - rel.3 x=90-2*α
<MOP=α+x+β=α+90-2*α+β=90+β-α -rel.1
<MOP=360-<AOP-<AOC-<MOC=360-β-AOC-α
<AOC=180-2*α
deci, <MOP=360-α-β-(180-2*α)=180-β+α -rel.2
din rel. 1 si 2 90+β-α=180-β+α β=45+α
<MOP=α+x+β=α+x+45+α=2*α+x+45 inlocuind rel.3 <MOP=90+45=135
x=masura <BOD
<COD=90=2*α+x - rel.3 x=90-2*α
<MOP=α+x+β=α+90-2*α+β=90+β-α -rel.1
<MOP=360-<AOP-<AOC-<MOC=360-β-AOC-α
<AOC=180-2*α
deci, <MOP=360-α-β-(180-2*α)=180-β+α -rel.2
din rel. 1 si 2 90+β-α=180-β+α β=45+α
<MOP=α+x+β=α+x+45+α=2*α+x+45 inlocuind rel.3 <MOP=90+45=135