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Finding the Fourth Proportional to 140.72, 210.90 and 49.31

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Solution

The fourth proportional to 140.72, 210.90 and 49.31 is: 73.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.72 : 210.90 = 49.31 : x
  2. Step 2: Convert to fraction form
    140.72/210.90 = 49.31/x
  3. Step 3: Cross multiply
    140.72x = 210.90 × 49.31
  4. Step 4: Simplify right side
    140.72x = 10,399.12
  5. Step 5: Solve for x
    x = 10,399.12/140.72
  6. Step 6: Final answer
    x = 73.90

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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.