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Finding the Fourth Proportional to 255.78, 382.98 and 139.68

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Solution

The fourth proportional to 255.78, 382.98 and 139.68 is: 209.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    255.78 : 382.98 = 139.68 : x
  2. Step 2: Convert to fraction form
    255.78/382.98 = 139.68/x
  3. Step 3: Cross multiply
    255.78x = 382.98 × 139.68
  4. Step 4: Simplify right side
    255.78x = 53,494.65
  5. Step 5: Solve for x
    x = 53,494.65/255.78
  6. Step 6: Final answer
    x = 209.14

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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.