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Finding the Fourth Proportional to 806.31, 1,207.71 and 420.75

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Solution

The fourth proportional to 806.31, 1,207.71 and 420.75 is: 630.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.31 : 1,207.71 = 420.75 : x
  2. Step 2: Convert to fraction form
    806.31/1,207.71 = 420.75/x
  3. Step 3: Cross multiply
    806.31x = 1,207.71 × 420.75
  4. Step 4: Simplify right side
    806.31x = 508,143.98
  5. Step 5: Solve for x
    x = 508,143.98/806.31
  6. Step 6: Final answer
    x = 630.21

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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.