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Finding the Fourth Proportional to 139.79, 209.70 and 121.36

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Solution

The fourth proportional to 139.79, 209.70 and 121.36 is: 182.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.79 : 209.70 = 121.36 : x
  2. Step 2: Convert to fraction form
    139.79/209.70 = 121.36/x
  3. Step 3: Cross multiply
    139.79x = 209.70 × 121.36
  4. Step 4: Simplify right side
    139.79x = 25,449.19
  5. Step 5: Solve for x
    x = 25,449.19/139.79
  6. Step 6: Final answer
    x = 182.05

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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.