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Finding the Fourth Proportional to 125.40, 172.89 and 81.69

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Solution

The fourth proportional to 125.40, 172.89 and 81.69 is: 112.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    125.40 : 172.89 = 81.69 : x
  2. Step 2: Convert to fraction form
    125.40/172.89 = 81.69/x
  3. Step 3: Cross multiply
    125.40x = 172.89 × 81.69
  4. Step 4: Simplify right side
    125.40x = 14,123.38
  5. Step 5: Solve for x
    x = 14,123.38/125.40
  6. Step 6: Final answer
    x = 112.63

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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.