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Finding the Fourth Proportional to 31.78, 47.60 and 20.36

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Solution

The fourth proportional to 31.78, 47.60 and 20.36 is: 30.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.78 : 47.60 = 20.36 : x
  2. Step 2: Convert to fraction form
    31.78/47.60 = 20.36/x
  3. Step 3: Cross multiply
    31.78x = 47.60 × 20.36
  4. Step 4: Simplify right side
    31.78x = 969.14
  5. Step 5: Solve for x
    x = 969.14/31.78
  6. Step 6: Final answer
    x = 30.50

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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.