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Finding the Fourth Proportional to 140.40, 193.86 and 85.20

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Solution

The fourth proportional to 140.40, 193.86 and 85.20 is: 117.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.40 : 193.86 = 85.20 : x
  2. Step 2: Convert to fraction form
    140.40/193.86 = 85.20/x
  3. Step 3: Cross multiply
    140.40x = 193.86 × 85.20
  4. Step 4: Simplify right side
    140.40x = 16,516.87
  5. Step 5: Solve for x
    x = 16,516.87/140.40
  6. Step 6: Final answer
    x = 117.64

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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.