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Finding the Fourth Proportional to 39.47, 58.99 and 31.78

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Solution

The fourth proportional to 39.47, 58.99 and 31.78 is: 47.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.47 : 58.99 = 31.78 : x
  2. Step 2: Convert to fraction form
    39.47/58.99 = 31.78/x
  3. Step 3: Cross multiply
    39.47x = 58.99 × 31.78
  4. Step 4: Simplify right side
    39.47x = 1,874.70
  5. Step 5: Solve for x
    x = 1,874.70/39.47
  6. Step 6: Final answer
    x = 47.50

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.