a. cosα=23,cosβ=23cos\alpha =\frac{2}{3},cos\beta=\frac{2}{3}cosα=32,cosβ=32, y cosγ=13cos\gamma =\frac{1}{3}cosγ=31; b. α=48o,β=48o\alpha=48^o, \beta=48^oα=48o,β=48o, y γ=71o\gamma=71^oγ=71o