Please help me I don’t understand

Ill mark the brainliest if you me with the these three questions 7,8,9

When keisha installed a fence along the 200 foot perimeter of her rectangular back yard, she left an opening for a gate.in the diagram below, she used x to represent the length in feet of the gate? what is the value? a. 10 b. 20 c. 25 d. 30

30 ! the graph shows the number of siblings different students have. select from the drop-down menus to correctly complete the statement.