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Finding the Fourth Proportional to 288.20, 398.02 and 257.68

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Solution

The fourth proportional to 288.20, 398.02 and 257.68 is: 355.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    288.20 : 398.02 = 257.68 : x
  2. Step 2: Convert to fraction form
    288.20/398.02 = 257.68/x
  3. Step 3: Cross multiply
    288.20x = 398.02 × 257.68
  4. Step 4: Simplify right side
    288.20x = 102,561.79
  5. Step 5: Solve for x
    x = 102,561.79/288.20
  6. Step 6: Final answer
    x = 355.87

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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.