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Finding the Fourth Proportional to 79.71, 118.92 and 71.61

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Solution

The fourth proportional to 79.71, 118.92 and 71.61 is: 106.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.71 : 118.92 = 71.61 : x
  2. Step 2: Convert to fraction form
    79.71/118.92 = 71.61/x
  3. Step 3: Cross multiply
    79.71x = 118.92 × 71.61
  4. Step 4: Simplify right side
    79.71x = 8,515.86
  5. Step 5: Solve for x
    x = 8,515.86/79.71
  6. Step 6: Final answer
    x = 106.84

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.