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Finding the Fourth Proportional to 140.20, 209.92 and 78.34

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Solution

The fourth proportional to 140.20, 209.92 and 78.34 is: 117.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.20 : 209.92 = 78.34 : x
  2. Step 2: Convert to fraction form
    140.20/209.92 = 78.34/x
  3. Step 3: Cross multiply
    140.20x = 209.92 × 78.34
  4. Step 4: Simplify right side
    140.20x = 16,445.13
  5. Step 5: Solve for x
    x = 16,445.13/140.20
  6. Step 6: Final answer
    x = 117.30

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.