Sunday
May 19, 2013

Homework Help: direct variation

Posted by Teri on Wednesday, September 13, 2006 at 8:40pm.

could someone please help me with these problems i am having trouble.

If y=36 when x =6 find x when y = 42
If y=-18 when x=6 find x when y=6
If y =12 when x= 15 find x when y =21
If y=-6.6 when x=9.9 find y when x =6.6
If y=6 when x=(2/3)find x when y=12

those are the problems you dont have to do all just at least show me step by step how you arrived at the answer thank you so much for helping




take the first one:

y1/y2 = x1/x2

y1=36 x1 is 6
y2=42 x2 is ?
then
36/42=6/x solve for x
and
x=42*6/36 =7

check my thinking.


hyng bbncnnh gbgbn


These are proportion problems
(1) 6:36=x:42 Which is the same as (6*42)/36=x
(2)6:18=x:6 Which is the same as (6*6)/18=x
(3) 15:12=x:21 I think you can do them now
(4)9.9:-6.6=6.6:y Watch where the y is located here.
(5)(2/3):6=x:12 Be sure to handle the fraction correctly.

In general, a proportion is two ratios a:b=c:d
a and d are called the extremes and b and c the means.
The fundamental relation is a*d=b*c The product of the extremes = the product of the means.
You can also think of it in terms of fractions a/b = c/d. in terms of fractions both ratios are different names for the same fraction. One is a multiple of the other. In the first one we have
6:36 or 6/36=1/6
We want to find x such that x/42 = 1/6 so x=42*(1/6)
You can verify that 1/6 = 6/36 = 7/42.
The fraction 1/6 would be the fraction in lowest terms in integers. In some places finding that lowest reducible integer fraction is very important. Other times we can't find such an integer ratio, e.g. if the numbers are irrational.


If y =12 when x= 15 find x when y =21

y=kx 21

No one has answered this question yet.

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

algebra - Please please help, this is like the only thing i am having trouble ...
Math - I am doing Direct Variation in math. I dont understand how to do it. It ...
Math: Direct Variation - what are the formulas that illustrates direct blinear ...
algebra - Tell whether equation represents direct variation. If so, identify the...
Stuck on Algebra 1 - This is kind of like the first question I asked, and I'...
Algebra - For this problem, tell whether each relationship is a direct variation...
Algebra - Each ordered pair is a solution of a direct variation. Write the ...
math - This is about direct variation. The area a painter can paint varies ...
Algebra - This is about direct variation. The area a painter can paint varies ...
Math - I am confused with this problem, A 14.1 oz box of cereal costs $2.89. ...

For Further Reading

Search
Members
Community