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Finding the Fourth Proportional to 138.70, 207.98 and 66.50

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Solution

The fourth proportional to 138.70, 207.98 and 66.50 is: 99.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.70 : 207.98 = 66.50 : x
  2. Step 2: Convert to fraction form
    138.70/207.98 = 66.50/x
  3. Step 3: Cross multiply
    138.70x = 207.98 × 66.50
  4. Step 4: Simplify right side
    138.70x = 13,830.34
  5. Step 5: Solve for x
    x = 13,830.34/138.70
  6. Step 6: Final answer
    x = 99.72

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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.