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Finding the Fourth Proportional to 355.20, 489.64 and 256.80

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Solution

The fourth proportional to 355.20, 489.64 and 256.80 is: 354.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    355.20 : 489.64 = 256.80 : x
  2. Step 2: Convert to fraction form
    355.20/489.64 = 256.80/x
  3. Step 3: Cross multiply
    355.20x = 489.64 × 256.80
  4. Step 4: Simplify right side
    355.20x = 125,739.55
  5. Step 5: Solve for x
    x = 125,739.55/355.20
  6. Step 6: Final answer
    x = 354.00

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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.