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Finding the Fourth Proportional to 1,280.92, 1,920.72 and 415.12

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Solution

The fourth proportional to 1,280.92, 1,920.72 and 415.12 is: 622.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.92 : 1,920.72 = 415.12 : x
  2. Step 2: Convert to fraction form
    1,280.92/1,920.72 = 415.12/x
  3. Step 3: Cross multiply
    1,280.92x = 1,920.72 × 415.12
  4. Step 4: Simplify right side
    1,280.92x = 797,329.29
  5. Step 5: Solve for x
    x = 797,329.29/1,280.92
  6. Step 6: Final answer
    x = 622.47

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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.