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Finding the Fourth Proportional to 644.73, 889.59 and 420.72

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Solution

The fourth proportional to 644.73, 889.59 and 420.72 is: 580.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.73 : 889.59 = 420.72 : x
  2. Step 2: Convert to fraction form
    644.73/889.59 = 420.72/x
  3. Step 3: Cross multiply
    644.73x = 889.59 × 420.72
  4. Step 4: Simplify right side
    644.73x = 374,268.30
  5. Step 5: Solve for x
    x = 374,268.30/644.73
  6. Step 6: Final answer
    x = 580.50

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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.