Fill in the blanks to make the statements true:

Both x and y are said to vary ……… with each other if for some positive number k, xy = k.

Fill in the blanks to make the statements true:

When two quantities x and y are in ………. Proportion or vary ………… they are written as x ∝ y.

Fill in the blanks to make the statements true:

When two quantities x and y are in ………. Proportion or vary ………… they are written as x ∝ 1/y.

Fill in the blanks to make the statements true:

x and y are said to vary directly with each other if for some positive number k, ……… = k.

Fill in the blanks to make the statements true:

Two quantities are said to vary ……………. With each other if they increase (decrease) together in such a manner that the ratio of their corresponding values remains constant.