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Finding the Fourth Proportional to 639.99, 959.97 and 207.15

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Solution

The fourth proportional to 639.99, 959.97 and 207.15 is: 310.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.99 : 959.97 = 207.15 : x
  2. Step 2: Convert to fraction form
    639.99/959.97 = 207.15/x
  3. Step 3: Cross multiply
    639.99x = 959.97 × 207.15
  4. Step 4: Simplify right side
    639.99x = 198,857.79
  5. Step 5: Solve for x
    x = 198,857.79/639.99
  6. Step 6: Final answer
    x = 310.72

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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.