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Finding the Fourth Proportional to 666.72, 999.90 and 419.76

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Solution

The fourth proportional to 666.72, 999.90 and 419.76 is: 629.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.72 : 999.90 = 419.76 : x
  2. Step 2: Convert to fraction form
    666.72/999.90 = 419.76/x
  3. Step 3: Cross multiply
    666.72x = 999.90 × 419.76
  4. Step 4: Simplify right side
    666.72x = 419,718.02
  5. Step 5: Solve for x
    x = 419,718.02/666.72
  6. Step 6: Final answer
    x = 629.53

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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.