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Finding the Fourth Proportional to 148.10, 221.70 and 139.20

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Solution

The fourth proportional to 148.10, 221.70 and 139.20 is: 208.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    148.10 : 221.70 = 139.20 : x
  2. Step 2: Convert to fraction form
    148.10/221.70 = 139.20/x
  3. Step 3: Cross multiply
    148.10x = 221.70 × 139.20
  4. Step 4: Simplify right side
    148.10x = 30,860.64
  5. Step 5: Solve for x
    x = 30,860.64/148.10
  6. Step 6: Final answer
    x = 208.38

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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.