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Finding the Fourth Proportional to 79.86, 119.79 and 31.75

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Solution

The fourth proportional to 79.86, 119.79 and 31.75 is: 47.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.86 : 119.79 = 31.75 : x
  2. Step 2: Convert to fraction form
    79.86/119.79 = 31.75/x
  3. Step 3: Cross multiply
    79.86x = 119.79 × 31.75
  4. Step 4: Simplify right side
    79.86x = 3,803.33
  5. Step 5: Solve for x
    x = 3,803.33/79.86
  6. Step 6: Final answer
    x = 47.63

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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.