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Finding the Fourth Proportional to 148.56, 221.31 and 139.70

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Solution

The fourth proportional to 148.56, 221.31 and 139.70 is: 208.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    148.56 : 221.31 = 139.70 : x
  2. Step 2: Convert to fraction form
    148.56/221.31 = 139.70/x
  3. Step 3: Cross multiply
    148.56x = 221.31 × 139.70
  4. Step 4: Simplify right side
    148.56x = 30,915.90
  5. Step 5: Solve for x
    x = 30,915.90/148.56
  6. Step 6: Final answer
    x = 208.10

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.