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Finding the Fourth Proportional to 139.08, 208.64 and 84.28

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Solution

The fourth proportional to 139.08, 208.64 and 84.28 is: 126.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.08 : 208.64 = 84.28 : x
  2. Step 2: Convert to fraction form
    139.08/208.64 = 84.28/x
  3. Step 3: Cross multiply
    139.08x = 208.64 × 84.28
  4. Step 4: Simplify right side
    139.08x = 17,584.18
  5. Step 5: Solve for x
    x = 17,584.18/139.08
  6. Step 6: Final answer
    x = 126.43

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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.