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Finding the Fourth Proportional to 138.79, 207.87 and 100.15

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Solution

The fourth proportional to 138.79, 207.87 and 100.15 is: 150.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.79 : 207.87 = 100.15 : x
  2. Step 2: Convert to fraction form
    138.79/207.87 = 100.15/x
  3. Step 3: Cross multiply
    138.79x = 207.87 × 100.15
  4. Step 4: Simplify right side
    138.79x = 20,818.18
  5. Step 5: Solve for x
    x = 20,818.18/138.79
  6. Step 6: Final answer
    x = 150.00

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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.