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Finding the Fourth Proportional to 666.10, 999.60 and 391.90

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Solution

The fourth proportional to 666.10, 999.60 and 391.90 is: 588.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.10 : 999.60 = 391.90 : x
  2. Step 2: Convert to fraction form
    666.10/999.60 = 391.90/x
  3. Step 3: Cross multiply
    666.10x = 999.60 × 391.90
  4. Step 4: Simplify right side
    666.10x = 391,743.24
  5. Step 5: Solve for x
    x = 391,743.24/666.10
  6. Step 6: Final answer
    x = 588.11

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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.