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Finding the Fourth Proportional to 139.23, 208.31 and 84.40

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Solution

The fourth proportional to 139.23, 208.31 and 84.40 is: 126.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.23 : 208.31 = 84.40 : x
  2. Step 2: Convert to fraction form
    139.23/208.31 = 84.40/x
  3. Step 3: Cross multiply
    139.23x = 208.31 × 84.40
  4. Step 4: Simplify right side
    139.23x = 17,581.05
  5. Step 5: Solve for x
    x = 17,581.05/139.23
  6. Step 6: Final answer
    x = 126.27

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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.