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Finding the Fourth Proportional to 66.74, 100.12 and 21.09

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Solution

The fourth proportional to 66.74, 100.12 and 21.09 is: 31.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.74 : 100.12 = 21.09 : x
  2. Step 2: Convert to fraction form
    66.74/100.12 = 21.09/x
  3. Step 3: Cross multiply
    66.74x = 100.12 × 21.09
  4. Step 4: Simplify right side
    66.74x = 2,111.10
  5. Step 5: Solve for x
    x = 2,111.10/66.74
  6. Step 6: Final answer
    x = 31.63

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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.