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Finding the Fourth Proportional to 129.86, 179.31 and 100.70

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Solution

The fourth proportional to 129.86, 179.31 and 100.70 is: 139.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.86 : 179.31 = 100.70 : x
  2. Step 2: Convert to fraction form
    129.86/179.31 = 100.70/x
  3. Step 3: Cross multiply
    129.86x = 179.31 × 100.70
  4. Step 4: Simplify right side
    129.86x = 18,056.52
  5. Step 5: Solve for x
    x = 18,056.52/129.86
  6. Step 6: Final answer
    x = 139.05

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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.