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Finding the Fourth Proportional to 140.45, 210.85 and 91.71

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Solution

The fourth proportional to 140.45, 210.85 and 91.71 is: 137.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.45 : 210.85 = 91.71 : x
  2. Step 2: Convert to fraction form
    140.45/210.85 = 91.71/x
  3. Step 3: Cross multiply
    140.45x = 210.85 × 91.71
  4. Step 4: Simplify right side
    140.45x = 19,336.82
  5. Step 5: Solve for x
    x = 19,336.82/140.45
  6. Step 6: Final answer
    x = 137.68

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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.