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Finding the Fourth Proportional to 66.90, 100.29 and 54.09

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Solution

The fourth proportional to 66.90, 100.29 and 54.09 is: 81.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.90 : 100.29 = 54.09 : x
  2. Step 2: Convert to fraction form
    66.90/100.29 = 54.09/x
  3. Step 3: Cross multiply
    66.90x = 100.29 × 54.09
  4. Step 4: Simplify right side
    66.90x = 5,424.69
  5. Step 5: Solve for x
    x = 5,424.69/66.90
  6. Step 6: Final answer
    x = 81.09

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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.