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Finding the Fourth Proportional to 213.47, 319.90 and 85.07

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Solution

The fourth proportional to 213.47, 319.90 and 85.07 is: 127.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.47 : 319.90 = 85.07 : x
  2. Step 2: Convert to fraction form
    213.47/319.90 = 85.07/x
  3. Step 3: Cross multiply
    213.47x = 319.90 × 85.07
  4. Step 4: Simplify right side
    213.47x = 27,211.87
  5. Step 5: Solve for x
    x = 27,211.87/213.47
  6. Step 6: Final answer
    x = 127.48

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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.