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Finding the Fourth Proportional to 102.20, 140.98 and 64.85

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Solution

The fourth proportional to 102.20, 140.98 and 64.85 is: 89.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.20 : 140.98 = 64.85 : x
  2. Step 2: Convert to fraction form
    102.20/140.98 = 64.85/x
  3. Step 3: Cross multiply
    102.20x = 140.98 × 64.85
  4. Step 4: Simplify right side
    102.20x = 9,141.69
  5. Step 5: Solve for x
    x = 9,141.69/102.20
  6. Step 6: Final answer
    x = 89.45

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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.