anonymous one year ago The equation below shows the area of a trapezoid, A, with a height of 9 cm, and one base 35 cm. : A = 9 over 2(b + 35) Which of the following formulas correctly solves for the other base, b? b = 2A over 9 + 35 b = 2 multiplied by A over 9 - 35 b = 2 multiplied by A plus 35, all over 9 b = 2 multiplied by A minus 35, all over 9

1. anonymous

@zzr0ck3r

2. anonymous

can you help

3. anonymous

@wio

4. zzr0ck3r

$$A=\dfrac{9}{2(b+35)}$$ ?

5. anonymous

A=9/2 (b+35)

6. zzr0ck3r

$A=\dfrac{9}{2}(b+35)$?

7. anonymous

Yes

8. zzr0ck3r

multipply both sides by $$\dfrac{2}{9}$$ and what do you have?

9. zzr0ck3r

multiply*

10. anonymous

9/2b+ 315/1

11. anonymous

2/9b

12. zzr0ck3r

$$(\dfrac{2}{9})A=(\dfrac{\cancel{2}}{\cancel{9}})\dfrac{\cancel{9}}{\cancel{2}}(b+35)\\\dfrac{2}{9}A=b+35$$

13. zzr0ck3r

you with me?

14. anonymous

Yes

15. zzr0ck3r

subtract 35 from both sides

16. anonymous

@skullpatrol

17. anonymous

@wio

18. anonymous

@UsukiDoll

19. anonymous

@freckles

20. anonymous

Hello

21. UsukiDoll

so leaving off with what zzrocker said we are solving for b and the last step he did was $(\dfrac{2}{9})A=(\dfrac{\cancel{2}}{\cancel{9}})\dfrac{\cancel{9}}{\cancel{2}}(b+35)\\\dfrac{2}{9}A=b+35$

22. UsukiDoll

there's not that much left to do with this problem... if we want b by itself, what do we have to do?

23. anonymous

-35

24. anonymous

from each side

25. UsukiDoll

yes

26. UsukiDoll

$\frac{2}{9}A - 35 = b$ that's it :)

27. UsukiDoll

you're looking for this selection right? b = 2 multiplied by A over 9 - 35

28. anonymous

thanks @UsukiDoll

29. UsukiDoll

can I get a medal? :)

30. anonymous

i just did

31. UsukiDoll

thank you :)

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