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Finding the Fourth Proportional to 211.55, 317.32 and 81.58

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Solution

The fourth proportional to 211.55, 317.32 and 81.58 is: 122.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.55 : 317.32 = 81.58 : x
  2. Step 2: Convert to fraction form
    211.55/317.32 = 81.58/x
  3. Step 3: Cross multiply
    211.55x = 317.32 × 81.58
  4. Step 4: Simplify right side
    211.55x = 25,886.97
  5. Step 5: Solve for x
    x = 25,886.97/211.55
  6. Step 6: Final answer
    x = 122.37

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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.