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Finding the Fourth Proportional to 420.36, 580.12 and 405.66

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Solution

The fourth proportional to 420.36, 580.12 and 405.66 is: 559.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.36 : 580.12 = 405.66 : x
  2. Step 2: Convert to fraction form
    420.36/580.12 = 405.66/x
  3. Step 3: Cross multiply
    420.36x = 580.12 × 405.66
  4. Step 4: Simplify right side
    420.36x = 235,331.48
  5. Step 5: Solve for x
    x = 235,331.48/420.36
  6. Step 6: Final answer
    x = 559.83

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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.