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Finding the Fourth Proportional to 79.70, 119.60 and 31.61

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Solution

The fourth proportional to 79.70, 119.60 and 31.61 is: 47.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.70 : 119.60 = 31.61 : x
  2. Step 2: Convert to fraction form
    79.70/119.60 = 31.61/x
  3. Step 3: Cross multiply
    79.70x = 119.60 × 31.61
  4. Step 4: Simplify right side
    79.70x = 3,779.80
  5. Step 5: Solve for x
    x = 3,779.80/79.70
  6. Step 6: Final answer
    x = 47.43

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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.