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Finding the Fourth Proportional to 639.93, 959.88 and 381.72

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Solution

The fourth proportional to 639.93, 959.88 and 381.72 is: 572.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.93 : 959.88 = 381.72 : x
  2. Step 2: Convert to fraction form
    639.93/959.88 = 381.72/x
  3. Step 3: Cross multiply
    639.93x = 959.88 × 381.72
  4. Step 4: Simplify right side
    639.93x = 366,405.39
  5. Step 5: Solve for x
    x = 366,405.39/639.93
  6. Step 6: Final answer
    x = 572.57

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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.