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Finding the Fourth Proportional to 667.60, 921.09 and 405.70

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Solution

The fourth proportional to 667.60, 921.09 and 405.70 is: 559.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.60 : 921.09 = 405.70 : x
  2. Step 2: Convert to fraction form
    667.60/921.09 = 405.70/x
  3. Step 3: Cross multiply
    667.60x = 921.09 × 405.70
  4. Step 4: Simplify right side
    667.60x = 373,686.21
  5. Step 5: Solve for x
    x = 373,686.21/667.60
  6. Step 6: Final answer
    x = 559.75

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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.