Helppp me plzzz on 3 through 10

Find an equation of the line perpendicular to the graph.

Mr. brettler is hanging up a 5-foot tall rectangular welcome sign in the gym. he has drawn a sketch on a coordinate grid. he has the lower vertices of the sign at (9, –3) and (–6, –3). where would the upper vertices be on the grid?

Alayna wonders how much water it would take to fill her cup she drops her pencil in her cup and notices that it just fits diagonal the pencil is 17 cm long and the cup is 15 cm tall how much water can the cup hold