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Finding the Fourth Proportional to 256.15, 353.49 and 139.71

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Solution

The fourth proportional to 256.15, 353.49 and 139.71 is: 192.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.15 : 353.49 = 139.71 : x
  2. Step 2: Convert to fraction form
    256.15/353.49 = 139.71/x
  3. Step 3: Cross multiply
    256.15x = 353.49 × 139.71
  4. Step 4: Simplify right side
    256.15x = 49,387.68
  5. Step 5: Solve for x
    x = 49,387.68/256.15
  6. Step 6: Final answer
    x = 192.81

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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.