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Finding the Fourth Proportional to 421.72, 581.90 and 255.90

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Solution

The fourth proportional to 421.72, 581.90 and 255.90 is: 353.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.72 : 581.90 = 255.90 : x
  2. Step 2: Convert to fraction form
    421.72/581.90 = 255.90/x
  3. Step 3: Cross multiply
    421.72x = 581.90 × 255.90
  4. Step 4: Simplify right side
    421.72x = 148,908.85
  5. Step 5: Solve for x
    x = 148,908.85/421.72
  6. Step 6: Final answer
    x = 353.10

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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.