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Finding the Fourth Proportional to 98.79, 147.91 and 81.75

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Solution

The fourth proportional to 98.79, 147.91 and 81.75 is: 122.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.79 : 147.91 = 81.75 : x
  2. Step 2: Convert to fraction form
    98.79/147.91 = 81.75/x
  3. Step 3: Cross multiply
    98.79x = 147.91 × 81.75
  4. Step 4: Simplify right side
    98.79x = 12,091.23
  5. Step 5: Solve for x
    x = 12,091.23/98.79
  6. Step 6: Final answer
    x = 122.39

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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.