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Finding the Fourth Proportional to 639.07, 958.60 and 421.07

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Solution

The fourth proportional to 639.07, 958.60 and 421.07 is: 631.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.07 : 958.60 = 421.07 : x
  2. Step 2: Convert to fraction form
    639.07/958.60 = 421.07/x
  3. Step 3: Cross multiply
    639.07x = 958.60 × 421.07
  4. Step 4: Simplify right side
    639.07x = 403,637.70
  5. Step 5: Solve for x
    x = 403,637.70/639.07
  6. Step 6: Final answer
    x = 631.60

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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.