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Finding the Fourth Proportional to 138, 207.14 and 56.90

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Solution

The fourth proportional to 138, 207.14 and 56.90 is: 85.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    138 : 207.14 = 56.90 : x
  2. Step 2: Convert to fraction form
    138/207.14 = 56.90/x
  3. Step 3: Cross multiply
    138x = 207.14 × 56.90
  4. Step 4: Simplify right side
    138x = 11,786.27
  5. Step 5: Solve for x
    x = 11,786.27/138
  6. Step 6: Final answer
    x = 85.41

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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.