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Finding the Fourth Proportional to 639.21, 882.86 and 511.90

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Solution

The fourth proportional to 639.21, 882.86 and 511.90 is: 707.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.21 : 882.86 = 511.90 : x
  2. Step 2: Convert to fraction form
    639.21/882.86 = 511.90/x
  3. Step 3: Cross multiply
    639.21x = 882.86 × 511.90
  4. Step 4: Simplify right side
    639.21x = 451,936.03
  5. Step 5: Solve for x
    x = 451,936.03/639.21
  6. Step 6: Final answer
    x = 707.02

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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.