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Finding the Fourth Proportional to 98.58, 136.07 and 76.78

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Solution

The fourth proportional to 98.58, 136.07 and 76.78 is: 105.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.58 : 136.07 = 76.78 : x
  2. Step 2: Convert to fraction form
    98.58/136.07 = 76.78/x
  3. Step 3: Cross multiply
    98.58x = 136.07 × 76.78
  4. Step 4: Simplify right side
    98.58x = 10,447.45
  5. Step 5: Solve for x
    x = 10,447.45/98.58
  6. Step 6: Final answer
    x = 105.98

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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.