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Finding the Fourth Proportional to 639.64, 959.30 and 206.68

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Solution

The fourth proportional to 639.64, 959.30 and 206.68 is: 309.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.64 : 959.30 = 206.68 : x
  2. Step 2: Convert to fraction form
    639.64/959.30 = 206.68/x
  3. Step 3: Cross multiply
    639.64x = 959.30 × 206.68
  4. Step 4: Simplify right side
    639.64x = 198,268.12
  5. Step 5: Solve for x
    x = 198,268.12/639.64
  6. Step 6: Final answer
    x = 309.97

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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.