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Finding the Fourth Proportional to 138.39, 190.87 and 89.20

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Solution

The fourth proportional to 138.39, 190.87 and 89.20 is: 123.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.39 : 190.87 = 89.20 : x
  2. Step 2: Convert to fraction form
    138.39/190.87 = 89.20/x
  3. Step 3: Cross multiply
    138.39x = 190.87 × 89.20
  4. Step 4: Simplify right side
    138.39x = 17,025.60
  5. Step 5: Solve for x
    x = 17,025.60/138.39
  6. Step 6: Final answer
    x = 123.03

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.