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Finding the Fourth Proportional to 1,028.61, 1,420.07 and 680.31

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Solution

The fourth proportional to 1,028.61, 1,420.07 and 680.31 is: 939.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,028.61 : 1,420.07 = 680.31 : x
  2. Step 2: Convert to fraction form
    1,028.61/1,420.07 = 680.31/x
  3. Step 3: Cross multiply
    1,028.61x = 1,420.07 × 680.31
  4. Step 4: Simplify right side
    1,028.61x = 966,084.42
  5. Step 5: Solve for x
    x = 966,084.42/1,028.61
  6. Step 6: Final answer
    x = 939.21

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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.