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Finding the Fourth Proportional to 137.52, 189.78 and 81.51

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Solution

The fourth proportional to 137.52, 189.78 and 81.51 is: 112.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.52 : 189.78 = 81.51 : x
  2. Step 2: Convert to fraction form
    137.52/189.78 = 81.51/x
  3. Step 3: Cross multiply
    137.52x = 189.78 × 81.51
  4. Step 4: Simplify right side
    137.52x = 15,467.95
  5. Step 5: Solve for x
    x = 15,467.95/137.52
  6. Step 6: Final answer
    x = 112.48

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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.