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Finding the Fourth Proportional to 1,281.09, 1,768.05 and 721.70

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Solution

The fourth proportional to 1,281.09, 1,768.05 and 721.70 is: 996.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.09 : 1,768.05 = 721.70 : x
  2. Step 2: Convert to fraction form
    1,281.09/1,768.05 = 721.70/x
  3. Step 3: Cross multiply
    1,281.09x = 1,768.05 × 721.70
  4. Step 4: Simplify right side
    1,281.09x = 1,275,992.84
  5. Step 5: Solve for x
    x = 1,275,992.84/1,281.09
  6. Step 6: Final answer
    x = 996.02

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.