One circle has a circumference half as large as that of a second circle. Which ratio compares the diameter of the
first circle to the diameter of the second circle?

The diameter of the first circle is 1/2 the diameter of the second circle.

These are linear measurements.  This means that the ratio of the circumference, distance around, of two circles is the same as the ratio of their diameters, or distance across.

Step-by-step explanation:

given that triangle abc is transformed two times to get triangle

a"b"c"

first abc is transformed in to a'b'c' as follows:

the coordinates of a are (1,-1) and transformed into a'(-1,1)

similarly b (4,-2) became b'(-4,2) and

c(7,-2) became c'(-7,2)

i.e. (x,y) becomes (-x,-y)

this is nothing but reflection about a point here origin.

thus first transformation is reflection on the origin.

next is exactly shifting 3 units down

source: