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Finding the Fourth Proportional to 1,288.70, 1,778.28 and 791.48

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Solution

The fourth proportional to 1,288.70, 1,778.28 and 791.48 is: 1,092.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.70 : 1,778.28 = 791.48 : x
  2. Step 2: Convert to fraction form
    1,288.70/1,778.28 = 791.48/x
  3. Step 3: Cross multiply
    1,288.70x = 1,778.28 × 791.48
  4. Step 4: Simplify right side
    1,288.70x = 1,407,473.05
  5. Step 5: Solve for x
    x = 1,407,473.05/1,288.70
  6. Step 6: Final answer
    x = 1,092.17

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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.