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Finding the Fourth Proportional to 878.46, 1,211.67 and 645.18

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Solution

The fourth proportional to 878.46, 1,211.67 and 645.18 is: 889.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.46 : 1,211.67 = 645.18 : x
  2. Step 2: Convert to fraction form
    878.46/1,211.67 = 645.18/x
  3. Step 3: Cross multiply
    878.46x = 1,211.67 × 645.18
  4. Step 4: Simplify right side
    878.46x = 781,745.25
  5. Step 5: Solve for x
    x = 781,745.25/878.46
  6. Step 6: Final answer
    x = 889.90

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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.