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Finding the Fourth Proportional to 98.20, 147.15 and 86.68

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Solution

The fourth proportional to 98.20, 147.15 and 86.68 is: 129.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.20 : 147.15 = 86.68 : x
  2. Step 2: Convert to fraction form
    98.20/147.15 = 86.68/x
  3. Step 3: Cross multiply
    98.20x = 147.15 × 86.68
  4. Step 4: Simplify right side
    98.20x = 12,754.96
  5. Step 5: Solve for x
    x = 12,754.96/98.20
  6. Step 6: Final answer
    x = 129.89

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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.