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Finding the Fourth Proportional to 644.23, 888.90 and 420.22

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Solution

The fourth proportional to 644.23, 888.90 and 420.22 is: 579.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.23 : 888.90 = 420.22 : x
  2. Step 2: Convert to fraction form
    644.23/888.90 = 420.22/x
  3. Step 3: Cross multiply
    644.23x = 888.90 × 420.22
  4. Step 4: Simplify right side
    644.23x = 373,533.56
  5. Step 5: Solve for x
    x = 373,533.56/644.23
  6. Step 6: Final answer
    x = 579.81

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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.