Question

Two angle measures of a triangle are given what is the third angle measure 57 68 _ 90 40 __ 29 71 _

Answer 1

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