A26' long painting is how many yards long

What is the absolute value of the complex number -4-sqrt2i

What is the sum of the first 8 terms of the geometric series

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.