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Finding the Fourth Proportional to 878.29, 1,212 and 485.30

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Solution

The fourth proportional to 878.29, 1,212 and 485.30 is: 669.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.29 : 1,212 = 485.30 : x
  2. Step 2: Convert to fraction form
    878.29/1,212 = 485.30/x
  3. Step 3: Cross multiply
    878.29x = 1,212 × 485.30
  4. Step 4: Simplify right side
    878.29x = 588,183.60
  5. Step 5: Solve for x
    x = 588,183.60/878.29
  6. Step 6: Final answer
    x = 669.70

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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.