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Finding the Fourth Proportional to 121.60, 168.16 and 102.40

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Solution

The fourth proportional to 121.60, 168.16 and 102.40 is: 141.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.60 : 168.16 = 102.40 : x
  2. Step 2: Convert to fraction form
    121.60/168.16 = 102.40/x
  3. Step 3: Cross multiply
    121.60x = 168.16 × 102.40
  4. Step 4: Simplify right side
    121.60x = 17,219.58
  5. Step 5: Solve for x
    x = 17,219.58/121.60
  6. Step 6: Final answer
    x = 141.61

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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.