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Finding the Fourth Proportional to 354.90, 489.45 and 256.74

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Solution

The fourth proportional to 354.90, 489.45 and 256.74 is: 354.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    354.90 : 489.45 = 256.74 : x
  2. Step 2: Convert to fraction form
    354.90/489.45 = 256.74/x
  3. Step 3: Cross multiply
    354.90x = 489.45 × 256.74
  4. Step 4: Simplify right side
    354.90x = 125,661.39
  5. Step 5: Solve for x
    x = 125,661.39/354.90
  6. Step 6: Final answer
    x = 354.08

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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.