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Finding the Fourth Proportional to 209.20, 288.70 and 139.14

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Solution

The fourth proportional to 209.20, 288.70 and 139.14 is: 192.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.20 : 288.70 = 139.14 : x
  2. Step 2: Convert to fraction form
    209.20/288.70 = 139.14/x
  3. Step 3: Cross multiply
    209.20x = 288.70 × 139.14
  4. Step 4: Simplify right side
    209.20x = 40,168.81
  5. Step 5: Solve for x
    x = 40,168.81/209.20
  6. Step 6: Final answer
    x = 192.01

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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.