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Finding the Fourth Proportional to 102.20, 140.80 and 83.84

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Solution

The fourth proportional to 102.20, 140.80 and 83.84 is: 115.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.20 : 140.80 = 83.84 : x
  2. Step 2: Convert to fraction form
    102.20/140.80 = 83.84/x
  3. Step 3: Cross multiply
    102.20x = 140.80 × 83.84
  4. Step 4: Simplify right side
    102.20x = 11,804.67
  5. Step 5: Solve for x
    x = 11,804.67/102.20
  6. Step 6: Final answer
    x = 115.51

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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.