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Finding the Fourth Proportional to 137.35, 189.21 and 128.85

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Solution

The fourth proportional to 137.35, 189.21 and 128.85 is: 177.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.35 : 189.21 = 128.85 : x
  2. Step 2: Convert to fraction form
    137.35/189.21 = 128.85/x
  3. Step 3: Cross multiply
    137.35x = 189.21 × 128.85
  4. Step 4: Simplify right side
    137.35x = 24,379.71
  5. Step 5: Solve for x
    x = 24,379.71/137.35
  6. Step 6: Final answer
    x = 177.50

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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.