Statement Reason
Points A, B, and C form a triangle.
given
Let DE be a line passing through Band parallel to AC. definition of parallel lines
23 - 25 and 21 - 24
m21 = m 24 and m23 = m 25
m24+ m2 2 + m25 = 180°
m21 +22+ m23 = 180°
angle addition and definition of a straight line
substitution

On traditional maps, earth is represented in a flat plane, or by euclidean geometry. however, a globe is a more accurate model that comes from elliptical geometry.how does a globe represent the fact that there are no parallel lines in elliptical geometry? the equator is not parallel to any other latitudinal lines. the north and south poles are never connected by a geodesic. the geodesics connecting the north and south poles never intersect. the geodesics connecting the north and south poles intersect at both of the poles.