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Finding the Fourth Proportional to 644.55, 889.29 and 405.30

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Solution

The fourth proportional to 644.55, 889.29 and 405.30 is: 559.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.55 : 889.29 = 405.30 : x
  2. Step 2: Convert to fraction form
    644.55/889.29 = 405.30/x
  3. Step 3: Cross multiply
    644.55x = 889.29 × 405.30
  4. Step 4: Simplify right side
    644.55x = 360,429.24
  5. Step 5: Solve for x
    x = 360,429.24/644.55
  6. Step 6: Final answer
    x = 559.20

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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.