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Finding the Fourth Proportional to 209.51, 289.17 and 139.70

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Solution

The fourth proportional to 209.51, 289.17 and 139.70 is: 192.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.51 : 289.17 = 139.70 : x
  2. Step 2: Convert to fraction form
    209.51/289.17 = 139.70/x
  3. Step 3: Cross multiply
    209.51x = 289.17 × 139.70
  4. Step 4: Simplify right side
    209.51x = 40,395.60
  5. Step 5: Solve for x
    x = 40,395.60/209.51
  6. Step 6: Final answer
    x = 192.81

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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.