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Finding the Fourth Proportional to 66.88, 100.28 and 39.86

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Solution

The fourth proportional to 66.88, 100.28 and 39.86 is: 59.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.88 : 100.28 = 39.86 : x
  2. Step 2: Convert to fraction form
    66.88/100.28 = 39.86/x
  3. Step 3: Cross multiply
    66.88x = 100.28 × 39.86
  4. Step 4: Simplify right side
    66.88x = 3,997.16
  5. Step 5: Solve for x
    x = 3,997.16/66.88
  6. Step 6: Final answer
    x = 59.77

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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.