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Finding the Fourth Proportional to 1,280.38, 1,920.54 and 663.88

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Solution

The fourth proportional to 1,280.38, 1,920.54 and 663.88 is: 995.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.38 : 1,920.54 = 663.88 : x
  2. Step 2: Convert to fraction form
    1,280.38/1,920.54 = 663.88/x
  3. Step 3: Cross multiply
    1,280.38x = 1,920.54 × 663.88
  4. Step 4: Simplify right side
    1,280.38x = 1,275,008.10
  5. Step 5: Solve for x
    x = 1,275,008.10/1,280.38
  6. Step 6: Final answer
    x = 995.80

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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.