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Finding the Fourth Proportional to 257.71, 385.72 and 140.40

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Solution

The fourth proportional to 257.71, 385.72 and 140.40 is: 210.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.71 : 385.72 = 140.40 : x
  2. Step 2: Convert to fraction form
    257.71/385.72 = 140.40/x
  3. Step 3: Cross multiply
    257.71x = 385.72 × 140.40
  4. Step 4: Simplify right side
    257.71x = 54,154.74
  5. Step 5: Solve for x
    x = 54,154.74/257.71
  6. Step 6: Final answer
    x = 210.14

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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.