(question 13) please no links! only correct answers!!!

Don't know how to find x given these segment lengths

The tile along the edge of a triangular community pool needs to be replaced? ?

Delbert keeps track of total of the total number of points he earns on homework assignments, each of which is worth 60 points. at the end of the semester he has 810 points. write an equation for delbert’s average homework score a in terms of the number of assignments n.