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Finding the Fourth Proportional to 820.19, 1,230.78 and 454.61

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Solution

The fourth proportional to 820.19, 1,230.78 and 454.61 is: 682.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.19 : 1,230.78 = 454.61 : x
  2. Step 2: Convert to fraction form
    820.19/1,230.78 = 454.61/x
  3. Step 3: Cross multiply
    820.19x = 1,230.78 × 454.61
  4. Step 4: Simplify right side
    820.19x = 559,524.90
  5. Step 5: Solve for x
    x = 559,524.90/820.19
  6. Step 6: Final answer
    x = 682.19

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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.