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Finding the Fourth Proportional to 139.10, 208.68 and 57.90

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Solution

The fourth proportional to 139.10, 208.68 and 57.90 is: 86.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.10 : 208.68 = 57.90 : x
  2. Step 2: Convert to fraction form
    139.10/208.68 = 57.90/x
  3. Step 3: Cross multiply
    139.10x = 208.68 × 57.90
  4. Step 4: Simplify right side
    139.10x = 12,082.57
  5. Step 5: Solve for x
    x = 12,082.57/139.10
  6. Step 6: Final answer
    x = 86.86

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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.