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Finding the Fourth Proportional to 138.26, 206.94 and 128.30

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Solution

The fourth proportional to 138.26, 206.94 and 128.30 is: 192.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.26 : 206.94 = 128.30 : x
  2. Step 2: Convert to fraction form
    138.26/206.94 = 128.30/x
  3. Step 3: Cross multiply
    138.26x = 206.94 × 128.30
  4. Step 4: Simplify right side
    138.26x = 26,550.40
  5. Step 5: Solve for x
    x = 26,550.40/138.26
  6. Step 6: Final answer
    x = 192.03

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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.