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Finding the Fourth Proportional to 820, 1,230.36 and 478

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Solution

The fourth proportional to 820, 1,230.36 and 478 is: 717.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    820 : 1,230.36 = 478 : x
  2. Step 2: Convert to fraction form
    820/1,230.36 = 478/x
  3. Step 3: Cross multiply
    820x = 1,230.36 × 478
  4. Step 4: Simplify right side
    820x = 588,112.08
  5. Step 5: Solve for x
    x = 588,112.08/820
  6. Step 6: Final answer
    x = 717.21

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