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Finding the Fourth Proportional to 66.43, 99.67 and 20.79

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Solution

The fourth proportional to 66.43, 99.67 and 20.79 is: 31.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.43 : 99.67 = 20.79 : x
  2. Step 2: Convert to fraction form
    66.43/99.67 = 20.79/x
  3. Step 3: Cross multiply
    66.43x = 99.67 × 20.79
  4. Step 4: Simplify right side
    66.43x = 2,072.14
  5. Step 5: Solve for x
    x = 2,072.14/66.43
  6. Step 6: Final answer
    x = 31.19

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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.