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Finding the Fourth Proportional to 1,394.31, 2,091.32 and 420.39

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Solution

The fourth proportional to 1,394.31, 2,091.32 and 420.39 is: 630.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,394.31 : 2,091.32 = 420.39 : x
  2. Step 2: Convert to fraction form
    1,394.31/2,091.32 = 420.39/x
  3. Step 3: Cross multiply
    1,394.31x = 2,091.32 × 420.39
  4. Step 4: Simplify right side
    1,394.31x = 879,169.49
  5. Step 5: Solve for x
    x = 879,169.49/1,394.31
  6. Step 6: Final answer
    x = 630.54

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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.