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Finding the Fourth Proportional to 278.69, 417.80 and 139.77

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Solution

The fourth proportional to 278.69, 417.80 and 139.77 is: 209.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.69 : 417.80 = 139.77 : x
  2. Step 2: Convert to fraction form
    278.69/417.80 = 139.77/x
  3. Step 3: Cross multiply
    278.69x = 417.80 × 139.77
  4. Step 4: Simplify right side
    278.69x = 58,396.26
  5. Step 5: Solve for x
    x = 58,396.26/278.69
  6. Step 6: Final answer
    x = 209.54

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.