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Finding the Fourth Proportional to 668.10, 921.78 and 406.20

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Solution

The fourth proportional to 668.10, 921.78 and 406.20 is: 560.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    668.10 : 921.78 = 406.20 : x
  2. Step 2: Convert to fraction form
    668.10/921.78 = 406.20/x
  3. Step 3: Cross multiply
    668.10x = 921.78 × 406.20
  4. Step 4: Simplify right side
    668.10x = 374,427.04
  5. Step 5: Solve for x
    x = 374,427.04/668.10
  6. Step 6: Final answer
    x = 560.44

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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.