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Finding the Fourth Proportional to 1,380.81, 1,905.48 and 791.40

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Solution

The fourth proportional to 1,380.81, 1,905.48 and 791.40 is: 1,092.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.81 : 1,905.48 = 791.40 : x
  2. Step 2: Convert to fraction form
    1,380.81/1,905.48 = 791.40/x
  3. Step 3: Cross multiply
    1,380.81x = 1,905.48 × 791.40
  4. Step 4: Simplify right side
    1,380.81x = 1,507,996.87
  5. Step 5: Solve for x
    x = 1,507,996.87/1,380.81
  6. Step 6: Final answer
    x = 1,092.11

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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.