cos ∠ C=(a^2+b^2-c^2)/2*a*b=(7^2+2^2-8^2)/(2*7*2)=-11/28 ≈ -0,393
∠ C= γ ≈ 113 °
a^2=b^2+c^2-2*b*c*cos ∠ A
cos ∠ A=(b^2+c^2-a^2)/(2*b*c)=(2^2+8^2-7^2)/(2*2*8)=19/32 ≈ 0,593
∠ A = α ≈54 °
β =180 ° - α - γ =180 ° -113 ° -54 ° =13 °