a. cosα=−130,cosβ=530cos\alpha =-\frac{1}{\sqrt{30}},cos\beta=\frac{5}{\sqrt{30}}cosα=−301,cosβ=305, y cosγ=230cos\gamma =\frac{2}{\sqrt{30}}cosγ=302; b. α=101o,β=24o\alpha=101^o, \beta=24^oα=101o,β=24o, y γ=69o\gamma=69^oγ=69o