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Finding the Fourth Proportional to 139.10, 208.35 and 121.10

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Solution

The fourth proportional to 139.10, 208.35 and 121.10 is: 181.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.10 : 208.35 = 121.10 : x
  2. Step 2: Convert to fraction form
    139.10/208.35 = 121.10/x
  3. Step 3: Cross multiply
    139.10x = 208.35 × 121.10
  4. Step 4: Simplify right side
    139.10x = 25,231.19
  5. Step 5: Solve for x
    x = 25,231.19/139.10
  6. Step 6: Final answer
    x = 181.39

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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.