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Finding the Fourth Proportional to 98.78, 148.41 and 84.29

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Solution

The fourth proportional to 98.78, 148.41 and 84.29 is: 126.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.78 : 148.41 = 84.29 : x
  2. Step 2: Convert to fraction form
    98.78/148.41 = 84.29/x
  3. Step 3: Cross multiply
    98.78x = 148.41 × 84.29
  4. Step 4: Simplify right side
    98.78x = 12,508.74
  5. Step 5: Solve for x
    x = 12,508.74/98.78
  6. Step 6: Final answer
    x = 126.64

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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.