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Finding the Fourth Proportional to 138.38, 190.86 and 89.30

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Solution

The fourth proportional to 138.38, 190.86 and 89.30 is: 123.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.38 : 190.86 = 89.30 : x
  2. Step 2: Convert to fraction form
    138.38/190.86 = 89.30/x
  3. Step 3: Cross multiply
    138.38x = 190.86 × 89.30
  4. Step 4: Simplify right side
    138.38x = 17,043.80
  5. Step 5: Solve for x
    x = 17,043.80/138.38
  6. Step 6: Final answer
    x = 123.17

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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.