exterior angle of a triangle

line font diagram brand drawing text cartoon circle presentation document wing vehicle wheel logo iron sketch exterior angle triangle science education angle triangle vector isolated white interior formula calculate shape measurement sum flat mathematics geometry planimetry plane education school university science study learning side degree radian corner straight line isosceles equilateral scalene equal lengths vertices polygon direction supplementary angles theorem student outside reflex definition relationship subtraction number smaller euclid#39aph39#s elements greater non-adjacent figure