SOLUTION: If y varies jointly as w and x, fill in the missing values. Also, find the constant of proportionality. W X Y 45.4 18.2 121 19.5 41.5 ___ ___

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: If y varies jointly as w and x, fill in the missing values. Also, find the constant of proportionality. W X Y 45.4 18.2 121 19.5 41.5 ___ ___      Log On


   

Question 1182907: If y varies jointly as w and x, fill in the missing values. Also, find the constant of proportionality.

W X Y
45.4 18.2 121
19.5 41.5 ___
___ 8.8 155
12.4 ___ 79.9
Found 2 solutions by josgarithmetic, MathLover1:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Your chart will look better if done inside of the PRE tags. 
W	    X	         Y
45.4	   18.2 	121
19.5       41.5	        ___
___        8.8	        155
12.4	   ___      	79.9

You would start by using the description as y=kxy for the variation constant, k. Use your first row set of values to help find the value for k.
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Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
Joint variation problems are solved using the equation
y+=+kxw
W ..........X ..........Y
45.4... 18.2 ...121
19.5... 41.5... ___
___ ....8.8.... 155
12.4.... ___ ...79.9
use first row to calaculate k

121=+k%2A18.2%2A45.4
121= k*826.28
k=121%2F826.28
k=0.14643946362008037
then
y+=+0.14643946362008037%2Ax%2Aw
y=+0.14643946362008037%2A41.5%2A19.5
y=118.5061359345500394225
approximately y=118.5

155=+0.14643946362008037%2A8.8%2Aw
155=+1.288667279856707256%2Aw
w=155%2F1.288667279856707256
w=120.2793
approximately w=120.3

y+=+0.14643946362008037%2Ax%2Aw
79.9=+0.14643946362008037%2Ax%2A12.4
79.9+=+1.81585%2A+x
x=79.9%2F1.81585
x=44.00143183633
approximately x=44

complete table:

W ..........X ..........Y
45.4... 18.2 ...121
19.5... 41.5... 118.5
120.3 ....8.8.... 155
12.4.... 44 ...79.9