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Finding the Fourth Proportional to 211.39, 317.22 and 81.48

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Solution

The fourth proportional to 211.39, 317.22 and 81.48 is: 122.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.39 : 317.22 = 81.48 : x
  2. Step 2: Convert to fraction form
    211.39/317.22 = 81.48/x
  3. Step 3: Cross multiply
    211.39x = 317.22 × 81.48
  4. Step 4: Simplify right side
    211.39x = 25,847.97
  5. Step 5: Solve for x
    x = 25,847.97/211.39
  6. Step 6: Final answer
    x = 122.28

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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.