Given a circle with measures of (c, d, and r) and a circle with measures of (c', d', and r'), what is r' if c c' = 3.0 and d = 12.0?

a) 2
b) 4
c) 8
d) 12

edit: the answer is a) 2

we know that

The circumference of a circle is equal to

where

D is the diameter of the circle

In this problem we have

the circumference of the circle is

------> equation A

the circumference of the circle is

------> equation B

and the ratio of the circumference of the circle to the circumference of the circle is

------> equation C

Substitute the equation A and equation B in the equation C

Find the radius r'

therefore

the answer is  the option A

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12

#15. square

step-by-step explanation:

because quadrilatural (idk how to spell it) means somthing that is not 3d or like, equal sides (or somthing like that   you know what i meanz)

hope this halps!

bai!