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Finding the Fourth Proportional to 421.78, 581.78 and 255.82

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Solution

The fourth proportional to 421.78, 581.78 and 255.82 is: 352.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.78 : 581.78 = 255.82 : x
  2. Step 2: Convert to fraction form
    421.78/581.78 = 255.82/x
  3. Step 3: Cross multiply
    421.78x = 581.78 × 255.82
  4. Step 4: Simplify right side
    421.78x = 148,830.96
  5. Step 5: Solve for x
    x = 148,830.96/421.78
  6. Step 6: Final answer
    x = 352.86

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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.