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Finding the Fourth Proportional to 639.65, 959.65 and 206.84

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Solution

The fourth proportional to 639.65, 959.65 and 206.84 is: 310.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.65 : 959.65 = 206.84 : x
  2. Step 2: Convert to fraction form
    639.65/959.65 = 206.84/x
  3. Step 3: Cross multiply
    639.65x = 959.65 × 206.84
  4. Step 4: Simplify right side
    639.65x = 198,488.69
  5. Step 5: Solve for x
    x = 198,488.69/639.65
  6. Step 6: Final answer
    x = 310.31

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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.