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Finding the Fourth Proportional to 220.58, 330.78 and 81.72

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Solution

The fourth proportional to 220.58, 330.78 and 81.72 is: 122.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.58 : 330.78 = 81.72 : x
  2. Step 2: Convert to fraction form
    220.58/330.78 = 81.72/x
  3. Step 3: Cross multiply
    220.58x = 330.78 × 81.72
  4. Step 4: Simplify right side
    220.58x = 27,031.34
  5. Step 5: Solve for x
    x = 27,031.34/220.58
  6. Step 6: Final answer
    x = 122.55

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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.