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Finding the Fourth Proportional to 644.70, 882 and 642.87

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Solution

The fourth proportional to 644.70, 882 and 642.87 is: 879.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.70 : 882 = 642.87 : x
  2. Step 2: Convert to fraction form
    644.70/882 = 642.87/x
  3. Step 3: Cross multiply
    644.70x = 882 × 642.87
  4. Step 4: Simplify right side
    644.70x = 567,011.34
  5. Step 5: Solve for x
    x = 567,011.34/644.70
  6. Step 6: Final answer
    x = 879.50

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.