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Finding the Fourth Proportional to 85.18, 127.79 and 31.09

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Solution

The fourth proportional to 85.18, 127.79 and 31.09 is: 46.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.18 : 127.79 = 31.09 : x
  2. Step 2: Convert to fraction form
    85.18/127.79 = 31.09/x
  3. Step 3: Cross multiply
    85.18x = 127.79 × 31.09
  4. Step 4: Simplify right side
    85.18x = 3,972.99
  5. Step 5: Solve for x
    x = 3,972.99/85.18
  6. Step 6: Final answer
    x = 46.64

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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.