48/72 and 6/9 propotional or not proportional

Sienna planned a trapezoid-shaped garden, as shown in the drawing below. she decides to change the length of the top of the trapezoid-shaped garden from 32 ft to 24 ft. which expression finds the change in the scale factor?

Anna is constructing a line segment that is congruent to another segment ab. for the construction, which tool should be used to mesure segment ab

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?