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Finding the Fourth Proportional to 666.45, 999.72 and 422.64

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Solution

The fourth proportional to 666.45, 999.72 and 422.64 is: 633.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.45 : 999.72 = 422.64 : x
  2. Step 2: Convert to fraction form
    666.45/999.72 = 422.64/x
  3. Step 3: Cross multiply
    666.45x = 999.72 × 422.64
  4. Step 4: Simplify right side
    666.45x = 422,521.66
  5. Step 5: Solve for x
    x = 422,521.66/666.45
  6. Step 6: Final answer
    x = 633.99

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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.