If DE ⊥ EF, then ∠DEF is a right angle, provide a counter example if false... help??

Read the equations in the table below. then drag a description of the situation and a table to represent each equation. indicate whether each of the relationships is proportional or non-proportional.

Find the ratios of the corresponding sides

6. sarah saved $12.75 every week for a number of weeks, w. she received an additional $25 during the last week in which she saved money. write and solve an equation to find the number of weeks, w, for which sarah had saved money if she has $114.25 now.