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Finding the Fourth Proportional to 98.31, 147.18 and 83.78

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Solution

The fourth proportional to 98.31, 147.18 and 83.78 is: 125.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.31 : 147.18 = 83.78 : x
  2. Step 2: Convert to fraction form
    98.31/147.18 = 83.78/x
  3. Step 3: Cross multiply
    98.31x = 147.18 × 83.78
  4. Step 4: Simplify right side
    98.31x = 12,330.87
  5. Step 5: Solve for x
    x = 12,330.87/98.31
  6. Step 6: Final answer
    x = 125.42

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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.