Anonymous
Anonymous asked in Science & MathematicsMathematics · 2 months ago

# Should I convert units before or after solving the problem? ?

For example, lets say we have a 6 foot by 4 foot rectangle, and the question asks us to find the area in square inches. Should I convert the feet to inches before finding the area, or find the area in square feet and convert to inches from there?

Relevance
• Yes that was also true.. You can still get the same answer when you convert ft to in before solving the area of the square, or convert is after you got the answer of the area of a square in square ft and convert it to inches..

• As long as you do the conversions correctly, the order you do them does not matter.

The part that you do have to be careful about is if your values have different labels:

6 feet by 18 inches

In this case, you'll have to convert one to match the other before you do the area, then convert to match what you are wanting.

• You should take every unit in same unit to solve problem. Every  unit can convert before or after to solve problem.But we can't use different unit to solve problem.

• 6*4=24 sq ft

24*144=3456 sq.in.

or

6*12*4*12=3456 sq in

as you like it - did you like it?

• Whatever's easier for you, as long as you don't try to combine measurements that are in different units.

For example, if you needed to add 3 feet with 6 inches, you can't add 3+6 first and figure out units later.

Or suppose you need to know how many gallons of paint are needed to cover a 6 foot by 4 foot rectangle to a depth of 1/2 inch. If you multiplied first you would get 12 square-foot-inches. Instead convert the feet to inches first, so that after multiplying you have cubic inches, which you can easily look up how to convert to gallons.

The conversion is simpler in linear units than in square or cubed units. You might, for example, know how many inches are in a foot but not remember offhand how many square inches are in a square foot.

• Its a matter of personal choice. However, it is probably better to make the conversions before that calculations, because you then do not forget to make the conversion.

So 6ft. x 4ft = 72 inches x 48 inches = 3456 sq.inches.

However,

4ft x 6ft = 24 sq.ft.

We now have to multiply by '144' because there are 12 x 12 = 144 sq.ins. in 1 sq.ft.

24 x 144 = 3456 sq.ins.

• Either before or after solving the problem, the conversion can take place.

6 feet by 4 feet

= 72 inches by 48 inches

= 3456 square inches

6 feet by 4 feet

= 24 feet^2

= 24 by 144 feet^2

= 3456 square inches

• Anonymous
2 months ago

It's easier to convert first as a general habit, or better yet, include it within the math.

6 ft x 12 inches/1 ft x 4 ft x 12 inches/1 foot

This way you know in your equation to cancel units.

It's easy enough in a simple example, 6ft x 4ft =24 sqft x 144 sqin/sqft =  3456 sq in

but then you get into measures like dollars per kilowatt-hour

at 10Amp 120 volt for 12 minutes converted to Euros.

Typically, to not miss, use one full equation.

• It's probably easiest to convert the linear measurements first.

6 feet * 12 in/ft = 72 inches

4 feet * 12 in/ft = 48 inches

Area = 72 inches * 48 inches = 3,456 sq. in.

You can do it the other way, but you have to use the correct conversion factor for *square* feet.

Remember, 1 sq. ft. = 12 inches * 12 inches = 144 sq. inches.

Doing it that way would be:

6 feet * 4 feet = 24 sq. ft.

24 sq. ft. * 144 sq. in./sq. ft.

= 3,456 sq. in.

As long as you don't accidentally think 1 sq. ft. = 12 sq. in. but instead use 144 sq. in. you can do it either way.

• Should not matter either way.  If you figure out the area in square feet and then convert, you only have 1 conversion to do.  But the answer will be the same