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Finding the Fourth Proportional to 138.79, 208.20 and 57.59

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Solution

The fourth proportional to 138.79, 208.20 and 57.59 is: 86.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.79 : 208.20 = 57.59 : x
  2. Step 2: Convert to fraction form
    138.79/208.20 = 57.59/x
  3. Step 3: Cross multiply
    138.79x = 208.20 × 57.59
  4. Step 4: Simplify right side
    138.79x = 11,990.24
  5. Step 5: Solve for x
    x = 11,990.24/138.79
  6. Step 6: Final answer
    x = 86.39

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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.