Question

In a circle, the circumference and diameter vary directly. Which of the following equations would allow you to find the diameter of a circle with a circumference of 154 if you know that in a second circle the diameter is 14 when the circumference is 44? A.154d = (14)(44) B.154/d = 44/14 C.14d = 154/44

Answer 1

john help me

Answer 2

lol I just started reading it hang on haha

Answer 3

ok :) i wait

Answer 4

ugh let me do that all over again!!! lol too many typos!!

Answer 5

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4.

A.3
B.5 1/3
C.18.75

Answer 6

I UNDERSTANED

Answer 7

haha are you sure? lol I'm gonna do it again anyways :P

Varying directly means

\[C = kD\]

Plug in what we know and solve for k:
44=k(14)
k=44/14

so now that we know what 'k' equals...and we want to solve for d...

\[154=(\frac{ 44 }{ 14 })(D)\]

Divide both sides by D to get...

\[\frac{ 154 }{ D }=\frac{ 44 }{ 14 }\]


So that looks like B to me...

there much better :)

Answer 8

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4. A.3 B.5 1/3 C.18.75

Answer 9

Now this new question...

again it varies directly so

\[x = ky\]

We know that x = 7.5 when y = 10 so

\[7.5 = k(10)\]

Divide both sides by 10 to solve for 'k'

\[k = \frac{ 7.5 }{ 10 }\]

Now that we know what 'k' equals...lets solve this problem...

what is 'x' when y = 4?

\[x = ky\]

\[x = \frac{ 7.5 }{ 10 }(4)\]

And we solve that to get...?

Answer 10

C?

Answer 11

7.5 times 4 = 30

30/10 = ...?

Answer 12

3

Answer 13

There you go

Answer 14

: If t varies as v, and t = 2 4/7 when v =13/14, find v when t = 2 1/4. A.2106/392 B.13/16 C.324/52

Answer 15

problem with fractions i kind stuck here

Answer 16

varies directly? or inversely?

Answer 17

I'm not sure

Answer 18

I'm going to assume directly

\[t = kv\]

t = 2 4/7 when v =13/14 so

*is that 24/7 or 2 4/7?
fraction or mixed number?

Answer 19

\[2 \frac{ 4 }{ 7 }\]

Answer 20

ahh okay a mixed number....convert that to an improper fraction for me...

Answer 21

Did you know how to?

Answer 22

So you take the denominator (7) and multiply it by the whole number (2)....and add the numerator to that..(4)

so 7 times 2 = 14....+ 4 = 18....and you put this over the original denominator

18/7 is our improper fraction...

so we have

\[t = kv\]

t = 18/7 when v =13/14 so

\[\frac{ 18 }{ 7 } = k(\frac{ 13 }{ 14 })\]

Now multiply both sides of the equation by 14/13 to isolate 'k'

\[k = \frac{ 18 }{ 7 } \times \frac{ 14 }{ 13 }\]

\[k = \frac{ 252 }{ 91 }\]

Now that we know what 'k' equals..we can solve this

Answer 23

ok

Answer 24

find v when t = 2 1/4.

Turning that into an improper fraction we have 9/4

so

\[t = kv\]

\[\frac{ 9 }{ 4 } = \frac{ 252 }{ 91} v\]

multiply both sides by 9/252 to isolate v...

\[v = \frac{ 9 }{ 4 } \times \frac{ 91 }{ 252 }\]

\[v = \frac{ 13 }{ 16 }\]

Answer 25

:) thnx i will safe this work

Answer 26

one sec i show one screen i have no clue how to solve this

Answer 27

@johnweldon1993

Answer 28

you know how to do this?

Answer 29

p ~ 1/v my answer but it doesn't match may be im wrong

Answer 30

that's weird....p = k/v is a proportion....it is inversely proportional...hmm I have no idea?

Maybe try a direct proportion?

pv = k?

idk no idea on this one

Answer 31

@johnweldon1993 one thing on screen they put that i just need to continue

Answer 32

@johnweldon1993

Answer 33

so they put the K_1 = thing? try putting "pv"

Answer 34

i can't remove

Answer 35

Yeah see I have no idea...

Answer 36

i have to put whats on grid

Answer 37

The volume (v) of a sphere varies directly as the cube of its diameter (d). Write this statement in algebraic language, using an equation with the variables c, v, and d.

Answer 38

\[C=\frac{ ? }{ ? }\]

Answer 39

same here they started C= ?/?

Answer 40

@johnweldon1993 ?