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Finding the Fourth Proportional to 102.12, 140.80 and 84.64

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Solution

The fourth proportional to 102.12, 140.80 and 84.64 is: 116.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.12 : 140.80 = 84.64 : x
  2. Step 2: Convert to fraction form
    102.12/140.80 = 84.64/x
  3. Step 3: Cross multiply
    102.12x = 140.80 × 84.64
  4. Step 4: Simplify right side
    102.12x = 11,917.31
  5. Step 5: Solve for x
    x = 11,917.31/102.12
  6. Step 6: Final answer
    x = 116.70

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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.