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Finding the Fourth Proportional to 667.76, 921.30 and 405.68

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Solution

The fourth proportional to 667.76, 921.30 and 405.68 is: 559.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.76 : 921.30 = 405.68 : x
  2. Step 2: Convert to fraction form
    667.76/921.30 = 405.68/x
  3. Step 3: Cross multiply
    667.76x = 921.30 × 405.68
  4. Step 4: Simplify right side
    667.76x = 373,752.98
  5. Step 5: Solve for x
    x = 373,752.98/667.76
  6. Step 6: Final answer
    x = 559.71

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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.