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Finding the Fourth Proportional to 130.79, 180.39 and 81.65

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Solution

The fourth proportional to 130.79, 180.39 and 81.65 is: 112.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.79 : 180.39 = 81.65 : x
  2. Step 2: Convert to fraction form
    130.79/180.39 = 81.65/x
  3. Step 3: Cross multiply
    130.79x = 180.39 × 81.65
  4. Step 4: Simplify right side
    130.79x = 14,729.60
  5. Step 5: Solve for x
    x = 14,729.60/130.79
  6. Step 6: Final answer
    x = 112.62

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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.