Help I don’t get this part of homework

The polygon tool to draw a rectangle with a length of 5 units and a height of 3 units. one of the sides of the rectangle falls on line ab , and the rectangle has a vertex of a. each segment on the grid represents 1 unit.

8litres of paint can cover 129.6 m². how much paint is required to paint an area of 243m²?

Which pair of numbers is relatively prime? a. 105 and 128 b. 130 and 273 c. 205 and 350 d. 273 and 333