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Finding the Fourth Proportional to 140.62, 210.78 and 91.90

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Solution

The fourth proportional to 140.62, 210.78 and 91.90 is: 137.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.62 : 210.78 = 91.90 : x
  2. Step 2: Convert to fraction form
    140.62/210.78 = 91.90/x
  3. Step 3: Cross multiply
    140.62x = 210.78 × 91.90
  4. Step 4: Simplify right side
    140.62x = 19,370.16
  5. Step 5: Solve for x
    x = 19,370.16/140.62
  6. Step 6: Final answer
    x = 137.75

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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.