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Finding the Fourth Proportional to 666.87, 920 and 397.63

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Solution

The fourth proportional to 666.87, 920 and 397.63 is: 548.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.87 : 920 = 397.63 : x
  2. Step 2: Convert to fraction form
    666.87/920 = 397.63/x
  3. Step 3: Cross multiply
    666.87x = 920 × 397.63
  4. Step 4: Simplify right side
    666.87x = 365,819.60
  5. Step 5: Solve for x
    x = 365,819.60/666.87
  6. Step 6: Final answer
    x = 548.56

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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.