Find the perimeter of the polygon if angle B is congruent to angle D. Please Help!

Ihave trouble finding the nth term of a linear sequence

Aflagpole broke in a storm. 77 7 meters are still sticking straight out of the ground, where it snapped, but the remaining piece has hinged over and touches the ground at a point 2424 24 meters away horizontally

Atourist boat is used for sightseeing in a nearby river. the boat travels 2.4 miles downstream and in the same amount of time, it travels 1.8 miles upstream. if the boat travels at an average speed of 21 miles per hour in the still water, find the current of the river.