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Finding the Fourth Proportional to 47.78, 71.65 and 18.89

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Solution

The fourth proportional to 47.78, 71.65 and 18.89 is: 28.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.78 : 71.65 = 18.89 : x
  2. Step 2: Convert to fraction form
    47.78/71.65 = 18.89/x
  3. Step 3: Cross multiply
    47.78x = 71.65 × 18.89
  4. Step 4: Simplify right side
    47.78x = 1,353.06
  5. Step 5: Solve for x
    x = 1,353.06/47.78
  6. Step 6: Final answer
    x = 28.32

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.