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Finding the Fourth Proportional to 665.64, 999.36 and 421.56

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Solution

The fourth proportional to 665.64, 999.36 and 421.56 is: 632.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.64 : 999.36 = 421.56 : x
  2. Step 2: Convert to fraction form
    665.64/999.36 = 421.56/x
  3. Step 3: Cross multiply
    665.64x = 999.36 × 421.56
  4. Step 4: Simplify right side
    665.64x = 421,290.20
  5. Step 5: Solve for x
    x = 421,290.20/665.64
  6. Step 6: Final answer
    x = 632.91

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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.