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Finding the Fourth Proportional to 639.95, 960.56 and 431.69

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Solution

The fourth proportional to 639.95, 960.56 and 431.69 is: 647.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.95 : 960.56 = 431.69 : x
  2. Step 2: Convert to fraction form
    639.95/960.56 = 431.69/x
  3. Step 3: Cross multiply
    639.95x = 960.56 × 431.69
  4. Step 4: Simplify right side
    639.95x = 414,664.15
  5. Step 5: Solve for x
    x = 414,664.15/639.95
  6. Step 6: Final answer
    x = 647.96

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.