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Finding the Fourth Proportional to 239.78, 359.49 and 212.78

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Solution

The fourth proportional to 239.78, 359.49 and 212.78 is: 319.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    239.78 : 359.49 = 212.78 : x
  2. Step 2: Convert to fraction form
    239.78/359.49 = 212.78/x
  3. Step 3: Cross multiply
    239.78x = 359.49 × 212.78
  4. Step 4: Simplify right side
    239.78x = 76,492.28
  5. Step 5: Solve for x
    x = 76,492.28/239.78
  6. Step 6: Final answer
    x = 319.01

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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.