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Finding the Fourth Proportional to 129.40, 168.40 and 129.40

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Solution

The fourth proportional to 129.40, 168.40 and 129.40 is: 168.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.40 : 168.40 = 129.40 : x
  2. Step 2: Convert to fraction form
    129.40/168.40 = 129.40/x
  3. Step 3: Cross multiply
    129.40x = 168.40 × 129.40
  4. Step 4: Simplify right side
    129.40x = 21,790.96
  5. Step 5: Solve for x
    x = 21,790.96/129.40
  6. Step 6: Final answer
    x = 168.40

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Why These Related Problems?

These problems maintain the same ratio (1.30) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.