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Finding the Fourth Proportional to 813.69, 1,220.54 and 381.15

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Solution

The fourth proportional to 813.69, 1,220.54 and 381.15 is: 571.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.69 : 1,220.54 = 381.15 : x
  2. Step 2: Convert to fraction form
    813.69/1,220.54 = 381.15/x
  3. Step 3: Cross multiply
    813.69x = 1,220.54 × 381.15
  4. Step 4: Simplify right side
    813.69x = 465,206.92
  5. Step 5: Solve for x
    x = 465,206.92/813.69
  6. Step 6: Final answer
    x = 571.73

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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.