c. Let's apply these principles in performing some conversions from other

systems to the metric system.

(1) Weight. Express 5 grains as milligrams.

(a) Step 1. Write the conversion factor as your **IF **ratio:

IF

1 gr

60 mg

(b) Step 2. Write the unknown factor as your **THEN **ratio:

THEN

5 gr

X mg

(c) Step 3. Solve for the unknown as in any other ratio and proportion

problem.

IF

1gr

= THEN

5 gr

60 mg

X mg

1X

5 60

=

X = 300 mg (answer)

(2) Volume. Express 4 fluid ounces as milliliters.

(a) Step 1. Write the conversion factor as your **IF **ratio:

IF

1 fl oz

30 ml

(b) Step 2. Write the unknown factor as your **THEN **ratio:

THEN

4 fl oz

X ml

(c) Step 3. Solve for the unknown.

IF

1 fl oz

THEN

4 fl oz

30 ml

=

X ml

1 X

4 30

=

X = 120 ml (answer)

MD0913

1-15

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