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Finding the Fourth Proportional to 140.22, 208.58 and 138.78

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Solution

The fourth proportional to 140.22, 208.58 and 138.78 is: 206.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.22 : 208.58 = 138.78 : x
  2. Step 2: Convert to fraction form
    140.22/208.58 = 138.78/x
  3. Step 3: Cross multiply
    140.22x = 208.58 × 138.78
  4. Step 4: Simplify right side
    140.22x = 28,946.04
  5. Step 5: Solve for x
    x = 28,946.04/140.22
  6. Step 6: Final answer
    x = 206.43

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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.