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Finding the Fourth Proportional to 137.45, 189.70 and 78.47

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Solution

The fourth proportional to 137.45, 189.70 and 78.47 is: 108.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.45 : 189.70 = 78.47 : x
  2. Step 2: Convert to fraction form
    137.45/189.70 = 78.47/x
  3. Step 3: Cross multiply
    137.45x = 189.70 × 78.47
  4. Step 4: Simplify right side
    137.45x = 14,884.61
  5. Step 5: Solve for x
    x = 14,884.61/137.45
  6. Step 6: Final answer
    x = 108.29

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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.