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Finding the Fourth Proportional to 420.90, 580.66 and 255.07

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Solution

The fourth proportional to 420.90, 580.66 and 255.07 is: 351.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.90 : 580.66 = 255.07 : x
  2. Step 2: Convert to fraction form
    420.90/580.66 = 255.07/x
  3. Step 3: Cross multiply
    420.90x = 580.66 × 255.07
  4. Step 4: Simplify right side
    420.90x = 148,108.95
  5. Step 5: Solve for x
    x = 148,108.95/420.90
  6. Step 6: Final answer
    x = 351.89

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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.