Be cause the ratio circumference: diameter is the same for every circle, is the ratio circumference: radius the same for every circle?

Absolutely !  You have just unlocked one of the great
immutable secrets of the universe.

Ratio of
               [ circumference / diameter ] =
ratio of
               [ circumference / (2 x radius) ] =
(1/2) ratio of
               [ circumference / diameter ] .

I don't know how else to say it, so I hope that did it for you.

All points to the left of zero on a horizontal number line are negative. a number line is a picture of a graduated straight line that serves as abstraction for real numbers. this number line can be extended to the left to represent numbers which are smaller than 0. such numbers are called negative numbersmark me brainliest

X=y+4 is the answe