How do I find the 4th side of a trapezoid when I am using polynomials for the sides

Tom travels between the two mile markers shown and then finds his average speed in miles per hour. select the three equations that represent this situation.

In the diagram below,abc is congruent to dec what is the value of x

The scatterplot represents the total fee for hours renting a bike. the line of best fit for the data is y = 6.855x + 10.215. which table shows the correct residual values for the data set?