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Finding the Fourth Proportional to 813.61, 1,220.15 and 265.66

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Solution

The fourth proportional to 813.61, 1,220.15 and 265.66 is: 398.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.61 : 1,220.15 = 265.66 : x
  2. Step 2: Convert to fraction form
    813.61/1,220.15 = 265.66/x
  3. Step 3: Cross multiply
    813.61x = 1,220.15 × 265.66
  4. Step 4: Simplify right side
    813.61x = 324,137.62
  5. Step 5: Solve for x
    x = 324,137.62/813.61
  6. Step 6: Final answer
    x = 398.40

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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.