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Finding the Fourth Proportional to 644.42, 889.42 and 395.90

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Solution

The fourth proportional to 644.42, 889.42 and 395.90 is: 546.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.42 : 889.42 = 395.90 : x
  2. Step 2: Convert to fraction form
    644.42/889.42 = 395.90/x
  3. Step 3: Cross multiply
    644.42x = 889.42 × 395.90
  4. Step 4: Simplify right side
    644.42x = 352,121.38
  5. Step 5: Solve for x
    x = 352,121.38/644.42
  6. Step 6: Final answer
    x = 546.42

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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.