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Finding the Fourth Proportional to 211.45, 317.18 and 81.49

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Solution

The fourth proportional to 211.45, 317.18 and 81.49 is: 122.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.45 : 317.18 = 81.49 : x
  2. Step 2: Convert to fraction form
    211.45/317.18 = 81.49/x
  3. Step 3: Cross multiply
    211.45x = 317.18 × 81.49
  4. Step 4: Simplify right side
    211.45x = 25,846.59
  5. Step 5: Solve for x
    x = 25,846.59/211.45
  6. Step 6: Final answer
    x = 122.24

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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.