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Finding the Fourth Proportional to 139.65, 208.56 and 121.25

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Solution

The fourth proportional to 139.65, 208.56 and 121.25 is: 181.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.65 : 208.56 = 121.25 : x
  2. Step 2: Convert to fraction form
    139.65/208.56 = 121.25/x
  3. Step 3: Cross multiply
    139.65x = 208.56 × 121.25
  4. Step 4: Simplify right side
    139.65x = 25,286.86
  5. Step 5: Solve for x
    x = 25,286.86/139.65
  6. Step 6: Final answer
    x = 181.07

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.