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Finding the Fourth Proportional to 139.87, 209.80 and 76.15

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Solution

The fourth proportional to 139.87, 209.80 and 76.15 is: 114.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.87 : 209.80 = 76.15 : x
  2. Step 2: Convert to fraction form
    139.87/209.80 = 76.15/x
  3. Step 3: Cross multiply
    139.87x = 209.80 × 76.15
  4. Step 4: Simplify right side
    139.87x = 15,975.22
  5. Step 5: Solve for x
    x = 15,975.22/139.87
  6. Step 6: Final answer
    x = 114.22

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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.