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Finding the Fourth Proportional to 137.90, 190.31 and 85.47

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Solution

The fourth proportional to 137.90, 190.31 and 85.47 is: 117.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.90 : 190.31 = 85.47 : x
  2. Step 2: Convert to fraction form
    137.90/190.31 = 85.47/x
  3. Step 3: Cross multiply
    137.90x = 190.31 × 85.47
  4. Step 4: Simplify right side
    137.90x = 16,265.37
  5. Step 5: Solve for x
    x = 16,265.37/137.90
  6. Step 6: Final answer
    x = 117.95

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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.