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Finding the Fourth Proportional to 851.90, 1,278.32 and 419.09

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Solution

The fourth proportional to 851.90, 1,278.32 and 419.09 is: 628.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.90 : 1,278.32 = 419.09 : x
  2. Step 2: Convert to fraction form
    851.90/1,278.32 = 419.09/x
  3. Step 3: Cross multiply
    851.90x = 1,278.32 × 419.09
  4. Step 4: Simplify right side
    851.90x = 535,722.64
  5. Step 5: Solve for x
    x = 535,722.64/851.90
  6. Step 6: Final answer
    x = 628.86

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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.