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Finding the Fourth Proportional to 257.79, 387.13 and 142.47

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Solution

The fourth proportional to 257.79, 387.13 and 142.47 is: 213.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.79 : 387.13 = 142.47 : x
  2. Step 2: Convert to fraction form
    257.79/387.13 = 142.47/x
  3. Step 3: Cross multiply
    257.79x = 387.13 × 142.47
  4. Step 4: Simplify right side
    257.79x = 55,154.05
  5. Step 5: Solve for x
    x = 55,154.05/257.79
  6. Step 6: Final answer
    x = 213.95

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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.