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Finding the Fourth Proportional to 239.84, 359.79 and 85.72

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Solution

The fourth proportional to 239.84, 359.79 and 85.72 is: 128.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    239.84 : 359.79 = 85.72 : x
  2. Step 2: Convert to fraction form
    239.84/359.79 = 85.72/x
  3. Step 3: Cross multiply
    239.84x = 359.79 × 85.72
  4. Step 4: Simplify right side
    239.84x = 30,840.30
  5. Step 5: Solve for x
    x = 30,840.30/239.84
  6. Step 6: Final answer
    x = 128.59

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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.