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Finding the Fourth Proportional to 138.33, 207.45 and 66.15

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Solution

The fourth proportional to 138.33, 207.45 and 66.15 is: 99.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.33 : 207.45 = 66.15 : x
  2. Step 2: Convert to fraction form
    138.33/207.45 = 66.15/x
  3. Step 3: Cross multiply
    138.33x = 207.45 × 66.15
  4. Step 4: Simplify right side
    138.33x = 13,722.82
  5. Step 5: Solve for x
    x = 13,722.82/138.33
  6. Step 6: Final answer
    x = 99.20

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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.