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Finding the Fourth Proportional to 137.56, 189.84 and 78.55

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Solution

The fourth proportional to 137.56, 189.84 and 78.55 is: 108.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.56 : 189.84 = 78.55 : x
  2. Step 2: Convert to fraction form
    137.56/189.84 = 78.55/x
  3. Step 3: Cross multiply
    137.56x = 189.84 × 78.55
  4. Step 4: Simplify right side
    137.56x = 14,912.18
  5. Step 5: Solve for x
    x = 14,912.18/137.56
  6. Step 6: Final answer
    x = 108.40

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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.