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Finding the Fourth Proportional to 139.47, 210.78 and 137.07

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Solution

The fourth proportional to 139.47, 210.78 and 137.07 is: 207.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.47 : 210.78 = 137.07 : x
  2. Step 2: Convert to fraction form
    139.47/210.78 = 137.07/x
  3. Step 3: Cross multiply
    139.47x = 210.78 × 137.07
  4. Step 4: Simplify right side
    139.47x = 28,891.61
  5. Step 5: Solve for x
    x = 28,891.61/139.47
  6. Step 6: Final answer
    x = 207.16

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.