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Finding the Fourth Proportional to 978.43, 1,350.29 and 642.53

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Solution

The fourth proportional to 978.43, 1,350.29 and 642.53 is: 886.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.43 : 1,350.29 = 642.53 : x
  2. Step 2: Convert to fraction form
    978.43/1,350.29 = 642.53/x
  3. Step 3: Cross multiply
    978.43x = 1,350.29 × 642.53
  4. Step 4: Simplify right side
    978.43x = 867,601.83
  5. Step 5: Solve for x
    x = 867,601.83/978.43
  6. Step 6: Final answer
    x = 886.73

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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.