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Finding the Fourth Proportional to 139.57, 209.28 and 52.87

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Solution

The fourth proportional to 139.57, 209.28 and 52.87 is: 79.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.57 : 209.28 = 52.87 : x
  2. Step 2: Convert to fraction form
    139.57/209.28 = 52.87/x
  3. Step 3: Cross multiply
    139.57x = 209.28 × 52.87
  4. Step 4: Simplify right side
    139.57x = 11,064.70
  5. Step 5: Solve for x
    x = 11,064.70/139.57
  6. Step 6: Final answer
    x = 79.28

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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.