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Finding the Fourth Proportional to 639.86, 959.78 and 201.11

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Solution

The fourth proportional to 639.86, 959.78 and 201.11 is: 301.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.86 : 959.78 = 201.11 : x
  2. Step 2: Convert to fraction form
    639.86/959.78 = 201.11/x
  3. Step 3: Cross multiply
    639.86x = 959.78 × 201.11
  4. Step 4: Simplify right side
    639.86x = 193,017.06
  5. Step 5: Solve for x
    x = 193,017.06/639.86
  6. Step 6: Final answer
    x = 301.66

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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.