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Finding the Fourth Proportional to 813.71, 1,220.69 and 265.78

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Solution

The fourth proportional to 813.71, 1,220.69 and 265.78 is: 398.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.71 : 1,220.69 = 265.78 : x
  2. Step 2: Convert to fraction form
    813.71/1,220.69 = 265.78/x
  3. Step 3: Cross multiply
    813.71x = 1,220.69 × 265.78
  4. Step 4: Simplify right side
    813.71x = 324,430.61
  5. Step 5: Solve for x
    x = 324,430.61/813.71
  6. Step 6: Final answer
    x = 398.70

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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.