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Finding the Fourth Proportional to 1,280.32, 1,921.09 and 663.69

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Solution

The fourth proportional to 1,280.32, 1,921.09 and 663.69 is: 995.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.32 : 1,921.09 = 663.69 : x
  2. Step 2: Convert to fraction form
    1,280.32/1,921.09 = 663.69/x
  3. Step 3: Cross multiply
    1,280.32x = 1,921.09 × 663.69
  4. Step 4: Simplify right side
    1,280.32x = 1,275,009.71
  5. Step 5: Solve for x
    x = 1,275,009.71/1,280.32
  6. Step 6: Final answer
    x = 995.85

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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.