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Finding the Fourth Proportional to 421.61, 581.86 and 255.87

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Solution

The fourth proportional to 421.61, 581.86 and 255.87 is: 353.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.61 : 581.86 = 255.87 : x
  2. Step 2: Convert to fraction form
    421.61/581.86 = 255.87/x
  3. Step 3: Cross multiply
    421.61x = 581.86 × 255.87
  4. Step 4: Simplify right side
    421.61x = 148,877.61
  5. Step 5: Solve for x
    x = 148,877.61/421.61
  6. Step 6: Final answer
    x = 353.12

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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.