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Finding the Fourth Proportional to 61.45, 84.74 and 39.31

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Solution

The fourth proportional to 61.45, 84.74 and 39.31 is: 54.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.45 : 84.74 = 39.31 : x
  2. Step 2: Convert to fraction form
    61.45/84.74 = 39.31/x
  3. Step 3: Cross multiply
    61.45x = 84.74 × 39.31
  4. Step 4: Simplify right side
    61.45x = 3,330.72
  5. Step 5: Solve for x
    x = 3,330.72/61.45
  6. Step 6: Final answer
    x = 54.20

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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.