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Finding the Fourth Proportional to 421.56, 581.40 and 255.76

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Solution

The fourth proportional to 421.56, 581.40 and 255.76 is: 352.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.56 : 581.40 = 255.76 : x
  2. Step 2: Convert to fraction form
    421.56/581.40 = 255.76/x
  3. Step 3: Cross multiply
    421.56x = 581.40 × 255.76
  4. Step 4: Simplify right side
    421.56x = 148,698.86
  5. Step 5: Solve for x
    x = 148,698.86/421.56
  6. Step 6: Final answer
    x = 352.73

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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.