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Finding the Fourth Proportional to 129.58, 178.81 and 71.36

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Solution

The fourth proportional to 129.58, 178.81 and 71.36 is: 98.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.58 : 178.81 = 71.36 : x
  2. Step 2: Convert to fraction form
    129.58/178.81 = 71.36/x
  3. Step 3: Cross multiply
    129.58x = 178.81 × 71.36
  4. Step 4: Simplify right side
    129.58x = 12,759.88
  5. Step 5: Solve for x
    x = 12,759.88/129.58
  6. Step 6: Final answer
    x = 98.47

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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.