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Finding the Fourth Proportional to 239.28, 358.80 and 85.20

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Solution

The fourth proportional to 239.28, 358.80 and 85.20 is: 127.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    239.28 : 358.80 = 85.20 : x
  2. Step 2: Convert to fraction form
    239.28/358.80 = 85.20/x
  3. Step 3: Cross multiply
    239.28x = 358.80 × 85.20
  4. Step 4: Simplify right side
    239.28x = 30,569.76
  5. Step 5: Solve for x
    x = 30,569.76/239.28
  6. Step 6: Final answer
    x = 127.76

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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.