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Finding the Fourth Proportional to 64.18, 96.28 and 20.85

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Solution

The fourth proportional to 64.18, 96.28 and 20.85 is: 31.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.18 : 96.28 = 20.85 : x
  2. Step 2: Convert to fraction form
    64.18/96.28 = 20.85/x
  3. Step 3: Cross multiply
    64.18x = 96.28 × 20.85
  4. Step 4: Simplify right side
    64.18x = 2,007.44
  5. Step 5: Solve for x
    x = 2,007.44/64.18
  6. Step 6: Final answer
    x = 31.28

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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.