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Finding the Fourth Proportional to 129.32, 193.79 and 80.40

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Solution

The fourth proportional to 129.32, 193.79 and 80.40 is: 120.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.32 : 193.79 = 80.40 : x
  2. Step 2: Convert to fraction form
    129.32/193.79 = 80.40/x
  3. Step 3: Cross multiply
    129.32x = 193.79 × 80.40
  4. Step 4: Simplify right side
    129.32x = 15,580.72
  5. Step 5: Solve for x
    x = 15,580.72/129.32
  6. Step 6: Final answer
    x = 120.48

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.