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Finding the Fourth Proportional to 821.13, 1,230.78 and 410.61

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Solution

The fourth proportional to 821.13, 1,230.78 and 410.61 is: 615.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.13 : 1,230.78 = 410.61 : x
  2. Step 2: Convert to fraction form
    821.13/1,230.78 = 410.61/x
  3. Step 3: Cross multiply
    821.13x = 1,230.78 × 410.61
  4. Step 4: Simplify right side
    821.13x = 505,370.58
  5. Step 5: Solve for x
    x = 505,370.58/821.13
  6. Step 6: Final answer
    x = 615.46

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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.