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Finding the Fourth Proportional to 668.66, 922.90 and 420.31

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Solution

The fourth proportional to 668.66, 922.90 and 420.31 is: 580.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    668.66 : 922.90 = 420.31 : x
  2. Step 2: Convert to fraction form
    668.66/922.90 = 420.31/x
  3. Step 3: Cross multiply
    668.66x = 922.90 × 420.31
  4. Step 4: Simplify right side
    668.66x = 387,906.55
  5. Step 5: Solve for x
    x = 387,906.55/668.66
  6. Step 6: Final answer
    x = 580.13

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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.