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Finding the Fourth Proportional to 129.13, 178.21 and 82.51

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Solution

The fourth proportional to 129.13, 178.21 and 82.51 is: 113.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.13 : 178.21 = 82.51 : x
  2. Step 2: Convert to fraction form
    129.13/178.21 = 82.51/x
  3. Step 3: Cross multiply
    129.13x = 178.21 × 82.51
  4. Step 4: Simplify right side
    129.13x = 14,705.31
  5. Step 5: Solve for x
    x = 14,705.31/129.13
  6. Step 6: Final answer
    x = 113.88

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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.