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Finding the Fourth Proportional to 639.12, 958.67 and 206.31

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Solution

The fourth proportional to 639.12, 958.67 and 206.31 is: 309.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.12 : 958.67 = 206.31 : x
  2. Step 2: Convert to fraction form
    639.12/958.67 = 206.31/x
  3. Step 3: Cross multiply
    639.12x = 958.67 × 206.31
  4. Step 4: Simplify right side
    639.12x = 197,783.21
  5. Step 5: Solve for x
    x = 197,783.21/639.12
  6. Step 6: Final answer
    x = 309.46

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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.