Start with this short video, then scroll down for the full guide.
Why This Matters for Nursing: Medication mixing, IV drip rates, and staffing calculations all use ratios. "Mix 1 part medication to 3 parts saline" or "1 nurse for every 4 patients" are ratios you'll use daily.
A ratio compares two quantities. It can be written three ways: - 1 to 3 - 1:3 - 1/3
A proportion states that two ratios are EQUAL: - 1:3 = 2:6 (both simplify to the same ratio)
Cross multiply to solve proportions!
If a/b = c/d, then a × d = b × c
Think of it as an "X" — multiply across the diagonal!
"Cross products are equal"
"The ratio of nurses to patients is 1:4" means: - Nurses : Patients = 1 : 4 - Nurses comes first because it's mentioned first
If there are 3 nurses, there are 12 patients (3:12 = 1:4)
Problem: If 2 tablets contain 500 mg, how many mg are in 5 tablets?
Setup:
2 tablets 5 tablets
--------- = -----------
500 mg x mg
Cross-multiply: - 2 × x = 500 × 5 - 2x = 2500 - x = 1250
Answer: 1,250 mg
Unlock all 61 study guides, unlimited practice quizzes, and your personalized study plan.
Start 3-Day Free Trial →3 days free • Cancel anytime • No commitment