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Finding the Fourth Proportional to 665.80, 999.16 and 405.89

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Solution

The fourth proportional to 665.80, 999.16 and 405.89 is: 609.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.80 : 999.16 = 405.89 : x
  2. Step 2: Convert to fraction form
    665.80/999.16 = 405.89/x
  3. Step 3: Cross multiply
    665.80x = 999.16 × 405.89
  4. Step 4: Simplify right side
    665.80x = 405,553.55
  5. Step 5: Solve for x
    x = 405,553.55/665.80
  6. Step 6: Final answer
    x = 609.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.