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Finding the Fourth Proportional to 411.72, 617.64 and 137.80

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Solution

The fourth proportional to 411.72, 617.64 and 137.80 is: 206.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    411.72 : 617.64 = 137.80 : x
  2. Step 2: Convert to fraction form
    411.72/617.64 = 137.80/x
  3. Step 3: Cross multiply
    411.72x = 617.64 × 137.80
  4. Step 4: Simplify right side
    411.72x = 85,110.79
  5. Step 5: Solve for x
    x = 85,110.79/411.72
  6. Step 6: Final answer
    x = 206.72

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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.