\(Sum\ of\ angles\ in\ triangle\ is\ 180^{\circ}\\\\
57^{\circ},68^{\circ},x\\
57+68+x=180\\
125+x=180\\
x=55^{\circ}\\\\
90^{\circ},40^{\circ},x\\
90+40+x=180\\
130+x=180\\
x=50^{\circ}\\\\29^{\circ},71^{\circ},x\\
29+71+x=180\\
100+x=180\\x=80^{\circ}\)
