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Finding the Fourth Proportional to 139.09, 208.23 and 78.07

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Solution

The fourth proportional to 139.09, 208.23 and 78.07 is: 116.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.09 : 208.23 = 78.07 : x
  2. Step 2: Convert to fraction form
    139.09/208.23 = 78.07/x
  3. Step 3: Cross multiply
    139.09x = 208.23 × 78.07
  4. Step 4: Simplify right side
    139.09x = 16,256.52
  5. Step 5: Solve for x
    x = 16,256.52/139.09
  6. Step 6: Final answer
    x = 116.88

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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.