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Finding the Fourth Proportional to 220.38, 330.30 and 128.90

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Solution

The fourth proportional to 220.38, 330.30 and 128.90 is: 193.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.38 : 330.30 = 128.90 : x
  2. Step 2: Convert to fraction form
    220.38/330.30 = 128.90/x
  3. Step 3: Cross multiply
    220.38x = 330.30 × 128.90
  4. Step 4: Simplify right side
    220.38x = 42,574.02
  5. Step 5: Solve for x
    x = 42,574.02/220.38
  6. Step 6: Final answer
    x = 193.18

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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.