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Finding the Fourth Proportional to 639.55, 958.70 and 407.73

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Solution

The fourth proportional to 639.55, 958.70 and 407.73 is: 611.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.55 : 958.70 = 407.73 : x
  2. Step 2: Convert to fraction form
    639.55/958.70 = 407.73/x
  3. Step 3: Cross multiply
    639.55x = 958.70 × 407.73
  4. Step 4: Simplify right side
    639.55x = 390,890.75
  5. Step 5: Solve for x
    x = 390,890.75/639.55
  6. Step 6: Final answer
    x = 611.20

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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.