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Finding the Fourth Proportional to 666.33, 998.09 and 421.64

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Solution

The fourth proportional to 666.33, 998.09 and 421.64 is: 631.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.33 : 998.09 = 421.64 : x
  2. Step 2: Convert to fraction form
    666.33/998.09 = 421.64/x
  3. Step 3: Cross multiply
    666.33x = 998.09 × 421.64
  4. Step 4: Simplify right side
    666.33x = 420,832.89
  5. Step 5: Solve for x
    x = 420,832.89/666.33
  6. Step 6: Final answer
    x = 631.57

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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.