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Finding the Fourth Proportional to 138, 208.51 and 136.79

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Solution

The fourth proportional to 138, 208.51 and 136.79 is: 206.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    138 : 208.51 = 136.79 : x
  2. Step 2: Convert to fraction form
    138/208.51 = 136.79/x
  3. Step 3: Cross multiply
    138x = 208.51 × 136.79
  4. Step 4: Simplify right side
    138x = 28,522.08
  5. Step 5: Solve for x
    x = 28,522.08/138
  6. Step 6: Final answer
    x = 206.68

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.