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Finding the Fourth Proportional to 125.31, 172.87 and 81.63

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Solution

The fourth proportional to 125.31, 172.87 and 81.63 is: 112.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.31 : 172.87 = 81.63 : x
  2. Step 2: Convert to fraction form
    125.31/172.87 = 81.63/x
  3. Step 3: Cross multiply
    125.31x = 172.87 × 81.63
  4. Step 4: Simplify right side
    125.31x = 14,111.38
  5. Step 5: Solve for x
    x = 14,111.38/125.31
  6. Step 6: Final answer
    x = 112.61

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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.