## Katieann16 2 years ago y varies jointly as x and z, and y = 32 m, x = 6 m, and z = 8 m. What is the value of y when x = 5 m and z = 12 m?

1. Mertsj

Can you write the joint variation equation for x y and z? Use k for the constant.

2. Katieann16

@jim_thompson5910

3. Mertsj

y=kxz

4. Mertsj

Now plug in the given values and find k.

5. jim_thompson5910

does Mertsj's response make sense?

6. Katieann16

a little, im still a little confused ..

7. Katieann16

so it would be 32m= k *5m*12m

8. jim_thompson5910

y = kxz we're given y = 32 m, x = 6 m, and z = 8 m plug all this in to get 32 = k*6*8 now solve for k Note: I think we can ignore the m's because I think they refer to meters (eg: x = 6 m means x is 6 meters long)

9. Katieann16

4?

10. jim_thompson5910

no

11. jim_thompson5910

32 = k*6*8 32 = k*48 k = ??

12. Katieann16

its 4?

13. jim_thompson5910

no it's not 4 divide both sides by 48 to solve for k

14. Katieann16

0.6?

15. jim_thompson5910

more like 0.667 but I would keep it as a fraction so k = 2/3

16. jim_thompson5910

y = kxz y = (2/3)xz y = (2/3)*5*12 plug in x = 5 and z = 12 y = ???

17. Katieann16

my choices are 90m, 4m, 40m, 9m

18. jim_thompson5910

5*12 is what

19. Katieann16

60

20. jim_thompson5910

now multiply that by 2 then divide that result by 3

21. Katieann16

4

22. jim_thompson5910

close, but not quite

23. Katieann16

40*

24. jim_thompson5910

yep

25. Katieann16

thank you(:

26. jim_thompson5910

you're welcome