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Finding the Fourth Proportional to 921.03, 1,378.31 and 642.03

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Solution

The fourth proportional to 921.03, 1,378.31 and 642.03 is: 960.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.03 : 1,378.31 = 642.03 : x
  2. Step 2: Convert to fraction form
    921.03/1,378.31 = 642.03/x
  3. Step 3: Cross multiply
    921.03x = 1,378.31 × 642.03
  4. Step 4: Simplify right side
    921.03x = 884,913.16
  5. Step 5: Solve for x
    x = 884,913.16/921.03
  6. Step 6: Final answer
    x = 960.79

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.