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Finding the Fourth Proportional to 139.34, 208.74 and 85.34

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Solution

The fourth proportional to 139.34, 208.74 and 85.34 is: 127.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.34 : 208.74 = 85.34 : x
  2. Step 2: Convert to fraction form
    139.34/208.74 = 85.34/x
  3. Step 3: Cross multiply
    139.34x = 208.74 × 85.34
  4. Step 4: Simplify right side
    139.34x = 17,813.87
  5. Step 5: Solve for x
    x = 17,813.87/139.34
  6. Step 6: Final answer
    x = 127.84

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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.