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Finding the Fourth Proportional to 420.78, 580.01 and 320.87

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Solution

The fourth proportional to 420.78, 580.01 and 320.87 is: 442.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.78 : 580.01 = 320.87 : x
  2. Step 2: Convert to fraction form
    420.78/580.01 = 320.87/x
  3. Step 3: Cross multiply
    420.78x = 580.01 × 320.87
  4. Step 4: Simplify right side
    420.78x = 186,103.30
  5. Step 5: Solve for x
    x = 186,103.30/420.78
  6. Step 6: Final answer
    x = 442.28

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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.