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Finding the Fourth Proportional to 820.50, 1,231.11 and 478.50

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Solution

The fourth proportional to 820.50, 1,231.11 and 478.50 is: 717.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.50 : 1,231.11 = 478.50 : x
  2. Step 2: Convert to fraction form
    820.50/1,231.11 = 478.50/x
  3. Step 3: Cross multiply
    820.50x = 1,231.11 × 478.50
  4. Step 4: Simplify right side
    820.50x = 589,086.14
  5. Step 5: Solve for x
    x = 589,086.14/820.50
  6. Step 6: Final answer
    x = 717.96

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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.