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Finding the Fourth Proportional to 139.32, 208.76 and 91.12

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Solution

The fourth proportional to 139.32, 208.76 and 91.12 is: 136.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.32 : 208.76 = 91.12 : x
  2. Step 2: Convert to fraction form
    139.32/208.76 = 91.12/x
  3. Step 3: Cross multiply
    139.32x = 208.76 × 91.12
  4. Step 4: Simplify right side
    139.32x = 19,022.21
  5. Step 5: Solve for x
    x = 19,022.21/139.32
  6. Step 6: Final answer
    x = 136.54

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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.