Question

in a traingle two angle 30°and 70° find the measure of third angle.

Answer 1

=180° -(30°+70°)
=180°-100°
=80°

Answer 2

$30 + 70 + x = 180 \\ 100 + x = 180 \\ x = 180 - 100 \\ x = 80$
third angle of triangle is 80