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Finding the Fourth Proportional to 138.09, 207.20 and 56.99

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Solution

The fourth proportional to 138.09, 207.20 and 56.99 is: 85.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.09 : 207.20 = 56.99 : x
  2. Step 2: Convert to fraction form
    138.09/207.20 = 56.99/x
  3. Step 3: Cross multiply
    138.09x = 207.20 × 56.99
  4. Step 4: Simplify right side
    138.09x = 11,807.01
  5. Step 5: Solve for x
    x = 11,807.01/138.09
  6. Step 6: Final answer
    x = 85.50

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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.