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Finding the Fourth Proportional to 98.78, 136.28 and 67.79

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Solution

The fourth proportional to 98.78, 136.28 and 67.79 is: 93.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.78 : 136.28 = 67.79 : x
  2. Step 2: Convert to fraction form
    98.78/136.28 = 67.79/x
  3. Step 3: Cross multiply
    98.78x = 136.28 × 67.79
  4. Step 4: Simplify right side
    98.78x = 9,237.40
  5. Step 5: Solve for x
    x = 9,237.40/98.78
  6. Step 6: Final answer
    x = 93.52

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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.