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Finding the Fourth Proportional to 98.55, 147.25 and 86.20

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Solution

The fourth proportional to 98.55, 147.25 and 86.20 is: 128.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.55 : 147.25 = 86.20 : x
  2. Step 2: Convert to fraction form
    98.55/147.25 = 86.20/x
  3. Step 3: Cross multiply
    98.55x = 147.25 × 86.20
  4. Step 4: Simplify right side
    98.55x = 12,692.69
  5. Step 5: Solve for x
    x = 12,692.69/98.55
  6. Step 6: Final answer
    x = 128.79

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.