Plz somebody me with all of them! i really really suck at math

Iam trying to solve a linear equation for the shoe size of someone 84" tall taking into consideration example 1 is 69" tall with a shoe size of 9 and example 2 is 72 inches tall with a shoe size of 11. i understand that the equation should be y=mx+b and that on the graph the answer is (3,2) but i just don't understand how to create the equation to solve for 84-inches and 60-inches tall questions. after two days, i need .

Pyramid shown has a square base that is 18 inches on each side has a surface area of 164 square inches what is the slant height

The track team ran a mile and a quarter during their practice how many kilometers did her team runs?