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Finding the Fourth Proportional to 755.28, 1,042.80 and 489.84

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Solution

The fourth proportional to 755.28, 1,042.80 and 489.84 is: 676.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    755.28 : 1,042.80 = 489.84 : x
  2. Step 2: Convert to fraction form
    755.28/1,042.80 = 489.84/x
  3. Step 3: Cross multiply
    755.28x = 1,042.80 × 489.84
  4. Step 4: Simplify right side
    755.28x = 510,805.15
  5. Step 5: Solve for x
    x = 510,805.15/755.28
  6. Step 6: Final answer
    x = 676.31

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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.