Photo above! how do i find the perimeter of this? im so confused

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 .

Lv beethoven software supplies customized software to a managed healthcare system. lv beethoven software's costs for the software is $1,723,000. lv beethoven software sells the software to the healthcare system for $3,816,981.10. overhead expenses are estimated at 47% of the selling price. what is lv beethoven software's net profit to the nearest dollar?

In δabc, m∠acb = 90°, cd ⊥ ab and m∠acd = 45°. find: a find cd, if bc = 3 in