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Finding the Fourth Proportional to 1,281.51, 1,917.90 and 819.60

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Solution

The fourth proportional to 1,281.51, 1,917.90 and 819.60 is: 1,226.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.51 : 1,917.90 = 819.60 : x
  2. Step 2: Convert to fraction form
    1,281.51/1,917.90 = 819.60/x
  3. Step 3: Cross multiply
    1,281.51x = 1,917.90 × 819.60
  4. Step 4: Simplify right side
    1,281.51x = 1,571,910.84
  5. Step 5: Solve for x
    x = 1,571,910.84/1,281.51
  6. Step 6: Final answer
    x = 1,226.61

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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.