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Finding the Fourth Proportional to 878.31, 1,212.03 and 485.30

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Solution

The fourth proportional to 878.31, 1,212.03 and 485.30 is: 669.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.31 : 1,212.03 = 485.30 : x
  2. Step 2: Convert to fraction form
    878.31/1,212.03 = 485.30/x
  3. Step 3: Cross multiply
    878.31x = 1,212.03 × 485.30
  4. Step 4: Simplify right side
    878.31x = 588,198.16
  5. Step 5: Solve for x
    x = 588,198.16/878.31
  6. Step 6: Final answer
    x = 669.69

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.