Solve the proportion 35 over 28 equals x over 4. What is the value of x?

2 Answers
Apr 9, 2017

Answer:

#x=5#

Explanation:

#35/28=x/4#
This is a ratio statement. The most common way to solve this is to use cross multiplication. I'll show you how to solve it that way (it's just a shortcut), but first I'll go through it step-by-step

First, our goal is to get rid of the denominators.
#cancel(28)*35/cancel(28)=x/4*28#
That's one denominatro cleared, now on to the next one:
#4*35=(28x)/cancel(4)*cancel(4)#
#4*35=28x# or #140=28x#

Now we need to isolate the #x#, so we just need to divide by #28# on both sides
#140/28=(cancel(28)x)/cancel(28)#
That simplifies to #5=x#

Now, to solve the same problem using cross multiplication, we begin with #35/28=x/4#. We just multiply the numerators (#35# and #x#) by #4# and #28# respectively, and then we divide by #28#.

It looks like this:
#35*4=28*x#
#(35*4)/28=x#
#140/28=x#
#5=x#

It just means skipping steps, but as long as you know what steps you're brushing over, you should be fine.

Apr 9, 2017

Answer:

See the entire solution process below:

Explanation:

First, we can rewrite this written expression as:

#35/28 = x/4#

Now, multiply each side of the equation by #color(red)(4)# to solve for #x# while keeping the equation balanced:

#color(red)(4) xx 35/28 = color(red)(4) xx x/4#

#cancel(color(red)(4)) xx 35/(color(red)(cancel(color(black)(28))) 7) = cancel(color(red)(4)) xx x/color(red)(cancel(color(black)(4)))#

#35/7 = x#

#5 = x#

#x = 5#