Solución

a. cosα=130,cosβ=530cos\alpha =-\frac{1}{\sqrt{30}},cos\beta=\frac{5}{\sqrt{30}}, y cosγ=230cos\gamma =\frac{2}{\sqrt{30}}; b. α=101o,β=24o\alpha=101^o, \beta=24^o, y γ=69o\gamma=69^o