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Finding the Fourth Proportional to 355.60, 489.72 and 257.20

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Solution

The fourth proportional to 355.60, 489.72 and 257.20 is: 354.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    355.60 : 489.72 = 257.20 : x
  2. Step 2: Convert to fraction form
    355.60/489.72 = 257.20/x
  3. Step 3: Cross multiply
    355.60x = 489.72 × 257.20
  4. Step 4: Simplify right side
    355.60x = 125,955.98
  5. Step 5: Solve for x
    x = 125,955.98/355.60
  6. Step 6: Final answer
    x = 354.21

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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.