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Finding the Fourth Proportional to 61.31, 84.57 and 39.45

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Solution

The fourth proportional to 61.31, 84.57 and 39.45 is: 54.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.31 : 84.57 = 39.45 : x
  2. Step 2: Convert to fraction form
    61.31/84.57 = 39.45/x
  3. Step 3: Cross multiply
    61.31x = 84.57 × 39.45
  4. Step 4: Simplify right side
    61.31x = 3,336.29
  5. Step 5: Solve for x
    x = 3,336.29/61.31
  6. Step 6: Final answer
    x = 54.42

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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.