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Finding the Fourth Proportional to 137.58, 189.85 and 78.56

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Solution

The fourth proportional to 137.58, 189.85 and 78.56 is: 108.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.58 : 189.85 = 78.56 : x
  2. Step 2: Convert to fraction form
    137.58/189.85 = 78.56/x
  3. Step 3: Cross multiply
    137.58x = 189.85 × 78.56
  4. Step 4: Simplify right side
    137.58x = 14,914.62
  5. Step 5: Solve for x
    x = 14,914.62/137.58
  6. Step 6: Final answer
    x = 108.41

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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.