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Finding the Fourth Proportional to 805.29, 1,111.05 and 639

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Solution

The fourth proportional to 805.29, 1,111.05 and 639 is: 881.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.29 : 1,111.05 = 639 : x
  2. Step 2: Convert to fraction form
    805.29/1,111.05 = 639/x
  3. Step 3: Cross multiply
    805.29x = 1,111.05 × 639
  4. Step 4: Simplify right side
    805.29x = 709,960.95
  5. Step 5: Solve for x
    x = 709,960.95/805.29
  6. Step 6: Final answer
    x = 881.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.