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Finding the Fourth Proportional to 354.21, 489.60 and 256.65

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Solution

The fourth proportional to 354.21, 489.60 and 256.65 is: 354.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    354.21 : 489.60 = 256.65 : x
  2. Step 2: Convert to fraction form
    354.21/489.60 = 256.65/x
  3. Step 3: Cross multiply
    354.21x = 489.60 × 256.65
  4. Step 4: Simplify right side
    354.21x = 125,655.84
  5. Step 5: Solve for x
    x = 125,655.84/354.21
  6. Step 6: Final answer
    x = 354.75

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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.