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Finding the Fourth Proportional to 639.45, 959.01 and 405.11

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Solution

The fourth proportional to 639.45, 959.01 and 405.11 is: 607.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.45 : 959.01 = 405.11 : x
  2. Step 2: Convert to fraction form
    639.45/959.01 = 405.11/x
  3. Step 3: Cross multiply
    639.45x = 959.01 × 405.11
  4. Step 4: Simplify right side
    639.45x = 388,499.75
  5. Step 5: Solve for x
    x = 388,499.75/639.45
  6. Step 6: Final answer
    x = 607.55

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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.