Mathematics/prealgerbra
posted by Joe .
how do I find a value of x that will make each proportion true??
12 = x
___ ___
16 20
and
8 = 14
__ ___
12 x
See previous post.
i still don't get it sorry
Cross multiply to find x.
Here's the first one; perhaps you can try the second one on your own.
12/16 = x/20
Take 12 * 20, which is 240. Take 16 * x, which is 16x. This is cross multiplying.
Therefore:
16x = 240
Divide both sides by 16 to solve for x.
You will find that x = 15
You can check by substituting 15 for x in your original problem.
12/16 = 15/20
This is a true statement, so you know the answer is correct.
I hope this is clearer.
Thanks for posting, MathGuru. Really good work.
Respond to this Question
Similar Questions

Algebra, math
how do I find a value of x that will make each proportion true? 
Math
i can't find these patterns. my mom and dad tried to. first problem 64,__,___,___,32 second problems 61,___, ___, ___, 81 
Math
I'm stumped on this one too: s e e d + i c e d  s p i c e c= ___ d=___ e=___ i= ___ p= ___ s=___ Hint: Solve for s and i. Then is e is even or odd? 
Chemistry Lab
Provide the correct coefficients to balance the following equation: ___ Fe(NH4)2(SO4)2·6H2O + ___ H2C2O4 + ___ K2C2O4 + ___ H2O2 > ___ K2Fe(C2O4)3·3H2O + ___ (NH4)2SO4 + ___ H2SO4 + ___ H2O I'm usually okay when it comes … 
science
freezing and thawing cycle that causes potholes in roads and breaks in rocks ___ ___ ___ ___ ___ ___ ___ ___ ____ 
statistics
Terms and Definitions matching ___ Statistics ___ Discrete variable ___ Statistics ___ Continuous variable ___ Population ___ Qualitative data ___ Population parameters ___ Quantitative data ___ Sample ___ Mean ___ Bias ___ Mode ___ … 
calculus
Leave any unneeded answer spaces blank. [Hint: use synthetic division to solve.] f(x) = (1x^3  3x^2  25x + 75)/(1x^3  19x^2 + 118x  240) the roots of f(x), in increasing order is/are.... ___, ___, ___ f(x) has holes when x is... … 
math
Show how to make one addend the next ten number. complete the new addition sentence. 6) 18+3=___ ___+___=___ 7) 27+24=___ ___+___=___ 
French
I had to fill in the blanks of this phrase with the following words: Word Bank: radoucira, irons, fera, etre, doux, devraient, pleuvra Phrase: La semaine prochaine, il est certain qu’il ne ___(1)___ pas du tout. Il ___(2)___ certainement … 
French
I would like to double check my fill in the blank answers. Merci! 26. Le film que nous ___(1)___ vu hier ___(2)___ sans aucun intérêt. Je me suis ___(3)___ pendant la ___(4)___. Nous ___(5)___ nous ___(6)___ même pas du titre du …