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Finding the Fourth Proportional to 209.40, 288.98 and 139.48

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Solution

The fourth proportional to 209.40, 288.98 and 139.48 is: 192.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.40 : 288.98 = 139.48 : x
  2. Step 2: Convert to fraction form
    209.40/288.98 = 139.48/x
  3. Step 3: Cross multiply
    209.40x = 288.98 × 139.48
  4. Step 4: Simplify right side
    209.40x = 40,306.93
  5. Step 5: Solve for x
    x = 40,306.93/209.40
  6. Step 6: Final answer
    x = 192.49

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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.