HELP URGENT pleaseee

How do the definitions, properties, and postulates you've learned about line segments, parallel lines, and angles to define the shapes of polygons

An airplane travels at an unknown elevation before it descends 3 miles to an elevation of 15 miles. find the elevation of the plane before its descen.

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?