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Finding the Fourth Proportional to 209.71, 289.33 and 139.87

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Solution

The fourth proportional to 209.71, 289.33 and 139.87 is: 192.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.71 : 289.33 = 139.87 : x
  2. Step 2: Convert to fraction form
    209.71/289.33 = 139.87/x
  3. Step 3: Cross multiply
    209.71x = 289.33 × 139.87
  4. Step 4: Simplify right side
    209.71x = 40,468.59
  5. Step 5: Solve for x
    x = 40,468.59/209.71
  6. Step 6: Final answer
    x = 192.97

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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.