चित्र (a ) से `._amu_g=(sin 60^@)/(sin 35^@)=1.50`
चित्र (b ) से `._amu_w=(sin 60^@)/(sin 41^@)=1.32`
चित्र (c ) से `._wmu_g=(._amu_g)/(._amu_w)=(sin i)/(sin r)`
`1.51/1.32=(sin 45^@)/(sin r) =0.707 /(sin r)`
`therefore sin r =1.32/1.51xx0.707`
=0.6181
`r=38.2^@`