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Finding the Fourth Proportional to 136.98, 205.41 and 72.78

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Solution

The fourth proportional to 136.98, 205.41 and 72.78 is: 109.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.98 : 205.41 = 72.78 : x
  2. Step 2: Convert to fraction form
    136.98/205.41 = 72.78/x
  3. Step 3: Cross multiply
    136.98x = 205.41 × 72.78
  4. Step 4: Simplify right side
    136.98x = 14,949.74
  5. Step 5: Solve for x
    x = 14,949.74/136.98
  6. Step 6: Final answer
    x = 109.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.