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Finding the Fourth Proportional to 61, 84.12 and 47.20

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Solution

The fourth proportional to 61, 84.12 and 47.20 is: 65.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    61 : 84.12 = 47.20 : x
  2. Step 2: Convert to fraction form
    61/84.12 = 47.20/x
  3. Step 3: Cross multiply
    61x = 84.12 × 47.20
  4. Step 4: Simplify right side
    61x = 3,970.46
  5. Step 5: Solve for x
    x = 3,970.46/61
  6. Step 6: Final answer
    x = 65.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.