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Finding the Fourth Proportional to 139.12, 207.15 and 138.16

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Solution

The fourth proportional to 139.12, 207.15 and 138.16 is: 205.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.12 : 207.15 = 138.16 : x
  2. Step 2: Convert to fraction form
    139.12/207.15 = 138.16/x
  3. Step 3: Cross multiply
    139.12x = 207.15 × 138.16
  4. Step 4: Simplify right side
    139.12x = 28,619.84
  5. Step 5: Solve for x
    x = 28,619.84/139.12
  6. Step 6: Final answer
    x = 205.72

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.