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Finding the Fourth Proportional to 137.16, 189.30 and 81.86

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Solution

The fourth proportional to 137.16, 189.30 and 81.86 is: 112.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.16 : 189.30 = 81.86 : x
  2. Step 2: Convert to fraction form
    137.16/189.30 = 81.86/x
  3. Step 3: Cross multiply
    137.16x = 189.30 × 81.86
  4. Step 4: Simplify right side
    137.16x = 15,496.10
  5. Step 5: Solve for x
    x = 15,496.10/137.16
  6. Step 6: Final answer
    x = 112.98

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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.