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Finding the Fourth Proportional to 139.08, 209.55 and 138.18

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Solution

The fourth proportional to 139.08, 209.55 and 138.18 is: 208.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.08 : 209.55 = 138.18 : x
  2. Step 2: Convert to fraction form
    139.08/209.55 = 138.18/x
  3. Step 3: Cross multiply
    139.08x = 209.55 × 138.18
  4. Step 4: Simplify right side
    139.08x = 28,955.62
  5. Step 5: Solve for x
    x = 28,955.62/139.08
  6. Step 6: Final answer
    x = 208.19

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.