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Finding the Fourth Proportional to 805.09, 1,109.95 and 639.85

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Solution

The fourth proportional to 805.09, 1,109.95 and 639.85 is: 882.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.09 : 1,109.95 = 639.85 : x
  2. Step 2: Convert to fraction form
    805.09/1,109.95 = 639.85/x
  3. Step 3: Cross multiply
    805.09x = 1,109.95 × 639.85
  4. Step 4: Simplify right side
    805.09x = 710,201.51
  5. Step 5: Solve for x
    x = 710,201.51/805.09
  6. Step 6: Final answer
    x = 882.14

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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.