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Finding the Fourth Proportional to 138.87, 208.02 and 90.63

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Solution

The fourth proportional to 138.87, 208.02 and 90.63 is: 135.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.87 : 208.02 = 90.63 : x
  2. Step 2: Convert to fraction form
    138.87/208.02 = 90.63/x
  3. Step 3: Cross multiply
    138.87x = 208.02 × 90.63
  4. Step 4: Simplify right side
    138.87x = 18,852.85
  5. Step 5: Solve for x
    x = 18,852.85/138.87
  6. Step 6: Final answer
    x = 135.76

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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.