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Finding the Fourth Proportional to 639.20, 958.52 and 206.40

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Solution

The fourth proportional to 639.20, 958.52 and 206.40 is: 309.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.20 : 958.52 = 206.40 : x
  2. Step 2: Convert to fraction form
    639.20/958.52 = 206.40/x
  3. Step 3: Cross multiply
    639.20x = 958.52 × 206.40
  4. Step 4: Simplify right side
    639.20x = 197,838.53
  5. Step 5: Solve for x
    x = 197,838.53/639.20
  6. Step 6: Final answer
    x = 309.51

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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.