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Finding the Fourth Proportional to 139.08, 208.26 and 91.08

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Solution

The fourth proportional to 139.08, 208.26 and 91.08 is: 136.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.08 : 208.26 = 91.08 : x
  2. Step 2: Convert to fraction form
    139.08/208.26 = 91.08/x
  3. Step 3: Cross multiply
    139.08x = 208.26 × 91.08
  4. Step 4: Simplify right side
    139.08x = 18,968.32
  5. Step 5: Solve for x
    x = 18,968.32/139.08
  6. Step 6: Final answer
    x = 136.38

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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.