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Finding the Fourth Proportional to 8,640, 12,960 and 3,169.28

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Solution

The fourth proportional to 8,640, 12,960 and 3,169.28 is: 4,753.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,640 : 12,960 = 3,169.28 : x
  2. Step 2: Convert to fraction form
    8,640/12,960 = 3,169.28/x
  3. Step 3: Cross multiply
    8,640x = 12,960 × 3,169.28
  4. Step 4: Simplify right side
    8,640x = 41,073,868.80
  5. Step 5: Solve for x
    x = 41,073,868.80/8,640
  6. Step 6: Final answer
    x = 4,753.92

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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.