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Finding the Fourth Proportional to 66.89, 100.21 and 39.75

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Solution

The fourth proportional to 66.89, 100.21 and 39.75 is: 59.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.89 : 100.21 = 39.75 : x
  2. Step 2: Convert to fraction form
    66.89/100.21 = 39.75/x
  3. Step 3: Cross multiply
    66.89x = 100.21 × 39.75
  4. Step 4: Simplify right side
    66.89x = 3,983.35
  5. Step 5: Solve for x
    x = 3,983.35/66.89
  6. Step 6: Final answer
    x = 59.55

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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.