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Finding the Fourth Proportional to 139.08, 208.72 and 87.76

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Solution

The fourth proportional to 139.08, 208.72 and 87.76 is: 131.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.08 : 208.72 = 87.76 : x
  2. Step 2: Convert to fraction form
    139.08/208.72 = 87.76/x
  3. Step 3: Cross multiply
    139.08x = 208.72 × 87.76
  4. Step 4: Simplify right side
    139.08x = 18,317.27
  5. Step 5: Solve for x
    x = 18,317.27/139.08
  6. Step 6: Final answer
    x = 131.70

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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.