# math

posted by on .

You want to produce a scale drawing of your living room, which is 24 ft by 15 ft. If you use a scale of 4 in=6 ft, what will be the dimensions of your scale drawing.

I think the dimensions are 16 ft by 10 ft. Is this right?

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No. Can you explain what you did to get that?

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I tried to make a proportion 4/6=x/24 and that's how I got 16. Then I got another proprtion 4/6=x/15 and I got 10. What did I do wrong?

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If you just think about how realistic your answer is, a drawing of those dimensions would be much too difficult to handle. That's a good way to know you've done something wrong.

Start by finding the scale for 1 foot. That should put you in the right direction.

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You may have used the scale 4 FEET = 6 feet when you should have done 4 INCHES = 6 feet. That's probably what you did wrong.

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Does 1 ft equals 1.5 in?

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is the answer 4 ft by 2.5 ft?

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To get the conversion factor for every foot, convert feet to inches.

4 in = 6 ft
4 in = 72 in
(divide by 4)
1 in = 18 in

For every 18 inches (1.5 ft), your scale will be only 1 inch. You must have done this backwards.

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what do you have to multiply?

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You're not actually multiplying. Sorry.

24 ft by 15 ft

Divide each by 1.5 so that it fits our conversion factor (1.5 ft = 1 in).

24/1.5 = 16 inches

Do the same thing with 15.

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is the answer 16 in by 10 in?

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Yup.