# How to Multiply a Ratio?

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### hightone

Oct 11, 2005, 2:26:32 AM10/11/05
to

Hi,

I need help to figure how to do this problem: 10 x 1:12.

My goal actually is to find the height of a ramp where the slope of
each section is 1:12 (what does that mean?) and the base is 10.00 m.

Thank you,
Tone

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### ticbol

Oct 13, 2005, 12:12:19 AM10/13/05
to

Slope is "vertical over horizontal". Fore a ramp, it is height over
base. Or it is the ratio of the height over the base. So if the slope
of the ramp is 1:12, that means where the height is 1, the base is 12.
Or, imagine a right triangle. The hypotenuse is the ramp. The vertical
leg is the height, and it is 1m. The horizontal leg is the base, and it
is 12 m.

If the base were 10 m only, what then is the corresponding height on
the ramp?

Imagine again the same right triangle but the horizontal leg is 10m
only. How do you get the height of this smaller right triangle?

One way is by proportion.
(height):(base) = (height):(base)
1:12 = h:10
That is the same as:
1/12 = h/10
Multiply both sides by 10,
10/12 = h
h = 10/12 = 5/6 = 0.8333 m.

### Dave Chamberlain

Oct 13, 2005, 12:12:20 AM10/13/05
to

hightone <tshivp...@gmail.com> wrote:

: Hi,

: I need help to figure how to do this problem: 10 x 1:12.

: My goal actually is to find the height of a ramp where the slope of
: each section is 1:12 (what does that mean?) and the base is 10.00 m.

"What does that mean?" - No offense, but I think it means you need
to go back to your math teacher and explain that you don't understand
the problem.

A ratio is a fraction, in this case it is dealing with a slope, so
think of it as "rise over run". How far up (or down) does the slope
change over the distance it goes. 1:12 will go up 1 inch for every
12 inches or 1 foot for every 12 feet or 1 mile for every 12 miles.
In your case, it will go up 1 meter for every 12 meters.

10 x 1:12 = 10 x 1/12

--

-davec
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### [Mr.] Lynn Kurtz

Oct 13, 2005, 12:12:25 AM10/13/05
to

On Tue, 11 Oct 2005 06:26:32 GMT, "hightone" <tshivp...@gmail.com>
wrote:

>
>Hi,
>
>I need help to figure how to do this problem: 10 x 1:12.
>
>My goal actually is to find the height of a ramp where the slope of
>each section is 1:12 (what does that mean?) and the base is 10.00 m.
>
>Thank you,
>Tone

The slope is 1 / 12 which means for every meter along the base it
rises 1 /12 meter. So if its base is 10 meters long it rises....?

--Lynn

### Duane Bozarth

Oct 13, 2005, 12:12:27 AM10/13/05
to

hightone wrote:
>
> Hi,
>
> I need help to figure how to do this problem: 10 x 1:12.
>
> My goal actually is to find the height of a ramp where the slope of
> each section is 1:12 (what does that mean?) and the base is 10.00 m.

1:12 --> rise/run --> for every unit in the horizontal direction it
rises 1/12 of that same unit.

So, if the base is 10 instead of 12, the height is 10/12.

### hightone

Oct 14, 2005, 12:43:53 AM10/14/05
to

Hi,

I want to thank you all that responded to the question. I really
appreciate you taking the time to help me.

Regards,
Tony