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Finding the Fourth Proportional to 668.20, 921.66 and 405.88

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Solution

The fourth proportional to 668.20, 921.66 and 405.88 is: 559.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    668.20 : 921.66 = 405.88 : x
  2. Step 2: Convert to fraction form
    668.20/921.66 = 405.88/x
  3. Step 3: Cross multiply
    668.20x = 921.66 × 405.88
  4. Step 4: Simplify right side
    668.20x = 374,083.36
  5. Step 5: Solve for x
    x = 374,083.36/668.20
  6. Step 6: Final answer
    x = 559.84

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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.