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Finding the Fourth Proportional to 130.85, 180.39 and 81.70

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Solution

The fourth proportional to 130.85, 180.39 and 81.70 is: 112.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.85 : 180.39 = 81.70 : x
  2. Step 2: Convert to fraction form
    130.85/180.39 = 81.70/x
  3. Step 3: Cross multiply
    130.85x = 180.39 × 81.70
  4. Step 4: Simplify right side
    130.85x = 14,737.86
  5. Step 5: Solve for x
    x = 14,737.86/130.85
  6. Step 6: Final answer
    x = 112.63

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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.