The ratio of the radii of two circles C1 and C2 is 1.5.
The ratio between the circumferences of circles C1 and C2 is
and the ratio between the areas of circles C1 and C2 is

Below in bold.

Step-by-step explanation:

The circumference is one dimensional so the ratio  is the same as the radii,

1.5.

The areas are 2 dimensional so the ratio is 1.5^2 = 2.25.

d. millimeters per hour.

step-by-step explanation:

we are given that,

carlo used a rain gauge to measure the amount of water his lawn is receiving from the sprinklers.

since, according to the options, we see that,

water cannot be measured by 'miles per hour', 'meters per second' and 'grams per seconds'.

we get that, the water can be measured by 'millimeters per hour'.

hence, the appropriate rate for describing the amount of water is 'millimeters per hour'.

that is the sum

step-by-step explanation:

there are no other answers without knowing the variables values