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Finding the Fourth Proportional to 669.90, 1,005.57 and 478.38

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Solution

The fourth proportional to 669.90, 1,005.57 and 478.38 is: 718.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.90 : 1,005.57 = 478.38 : x
  2. Step 2: Convert to fraction form
    669.90/1,005.57 = 478.38/x
  3. Step 3: Cross multiply
    669.90x = 1,005.57 × 478.38
  4. Step 4: Simplify right side
    669.90x = 481,044.58
  5. Step 5: Solve for x
    x = 481,044.58/669.90
  6. Step 6: Final answer
    x = 718.08

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.