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Finding the Fourth Proportional to 878.15, 1,211.82 and 485.18

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Solution

The fourth proportional to 878.15, 1,211.82 and 485.18 is: 669.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.15 : 1,211.82 = 485.18 : x
  2. Step 2: Convert to fraction form
    878.15/1,211.82 = 485.18/x
  3. Step 3: Cross multiply
    878.15x = 1,211.82 × 485.18
  4. Step 4: Simplify right side
    878.15x = 587,944.77
  5. Step 5: Solve for x
    x = 587,944.77/878.15
  6. Step 6: Final answer
    x = 669.53

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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.