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Finding the Fourth Proportional to 644.64, 889.39 and 395.70

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Solution

The fourth proportional to 644.64, 889.39 and 395.70 is: 545.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.64 : 889.39 = 395.70 : x
  2. Step 2: Convert to fraction form
    644.64/889.39 = 395.70/x
  3. Step 3: Cross multiply
    644.64x = 889.39 × 395.70
  4. Step 4: Simplify right side
    644.64x = 351,931.62
  5. Step 5: Solve for x
    x = 351,931.62/644.64
  6. Step 6: Final answer
    x = 545.94

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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.