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Finding the Fourth Proportional to 137.43, 189.66 and 78.43

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Solution

The fourth proportional to 137.43, 189.66 and 78.43 is: 108.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.43 : 189.66 = 78.43 : x
  2. Step 2: Convert to fraction form
    137.43/189.66 = 78.43/x
  3. Step 3: Cross multiply
    137.43x = 189.66 × 78.43
  4. Step 4: Simplify right side
    137.43x = 14,874.56
  5. Step 5: Solve for x
    x = 14,874.56/137.43
  6. Step 6: Final answer
    x = 108.23

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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.