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Finding the Fourth Proportional to 820.43, 1,230.78 and 409.49

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Solution

The fourth proportional to 820.43, 1,230.78 and 409.49 is: 614.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.43 : 1,230.78 = 409.49 : x
  2. Step 2: Convert to fraction form
    820.43/1,230.78 = 409.49/x
  3. Step 3: Cross multiply
    820.43x = 1,230.78 × 409.49
  4. Step 4: Simplify right side
    820.43x = 503,985.95
  5. Step 5: Solve for x
    x = 503,985.95/820.43
  6. Step 6: Final answer
    x = 614.30

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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.