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Finding the Fourth Proportional to 137.20, 189.32 and 85.44

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Solution

The fourth proportional to 137.20, 189.32 and 85.44 is: 117.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.20 : 189.32 = 85.44 : x
  2. Step 2: Convert to fraction form
    137.20/189.32 = 85.44/x
  3. Step 3: Cross multiply
    137.20x = 189.32 × 85.44
  4. Step 4: Simplify right side
    137.20x = 16,175.50
  5. Step 5: Solve for x
    x = 16,175.50/137.20
  6. Step 6: Final answer
    x = 117.90

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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.