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Finding the Fourth Proportional to 667.32, 920.78 and 387.57

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Solution

The fourth proportional to 667.32, 920.78 and 387.57 is: 534.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.32 : 920.78 = 387.57 : x
  2. Step 2: Convert to fraction form
    667.32/920.78 = 387.57/x
  3. Step 3: Cross multiply
    667.32x = 920.78 × 387.57
  4. Step 4: Simplify right side
    667.32x = 356,866.67
  5. Step 5: Solve for x
    x = 356,866.67/667.32
  6. Step 6: Final answer
    x = 534.77

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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.