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Finding the Fourth Proportional to 220.40, 304.20 and 142.80

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Solution

The fourth proportional to 220.40, 304.20 and 142.80 is: 197.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.40 : 304.20 = 142.80 : x
  2. Step 2: Convert to fraction form
    220.40/304.20 = 142.80/x
  3. Step 3: Cross multiply
    220.40x = 304.20 × 142.80
  4. Step 4: Simplify right side
    220.40x = 43,439.76
  5. Step 5: Solve for x
    x = 43,439.76/220.40
  6. Step 6: Final answer
    x = 197.10

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.