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Finding the Fourth Proportional to 209.28, 288.74 and 139.38

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Solution

The fourth proportional to 209.28, 288.74 and 139.38 is: 192.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.28 : 288.74 = 139.38 : x
  2. Step 2: Convert to fraction form
    209.28/288.74 = 139.38/x
  3. Step 3: Cross multiply
    209.28x = 288.74 × 139.38
  4. Step 4: Simplify right side
    209.28x = 40,244.58
  5. Step 5: Solve for x
    x = 40,244.58/209.28
  6. Step 6: Final answer
    x = 192.30

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.