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Finding the Fourth Proportional to 256.31, 353.70 and 139.87

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Solution

The fourth proportional to 256.31, 353.70 and 139.87 is: 193.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.31 : 353.70 = 139.87 : x
  2. Step 2: Convert to fraction form
    256.31/353.70 = 139.87/x
  3. Step 3: Cross multiply
    256.31x = 353.70 × 139.87
  4. Step 4: Simplify right side
    256.31x = 49,471.13
  5. Step 5: Solve for x
    x = 49,471.13/256.31
  6. Step 6: Final answer
    x = 193.02

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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.