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Finding the Fourth Proportional to 791.30, 1,091.78 and 511.55

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Solution

The fourth proportional to 791.30, 1,091.78 and 511.55 is: 705.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    791.30 : 1,091.78 = 511.55 : x
  2. Step 2: Convert to fraction form
    791.30/1,091.78 = 511.55/x
  3. Step 3: Cross multiply
    791.30x = 1,091.78 × 511.55
  4. Step 4: Simplify right side
    791.30x = 558,498.05
  5. Step 5: Solve for x
    x = 558,498.05/791.30
  6. Step 6: Final answer
    x = 705.80

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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.