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Finding the Fourth Proportional to 679.91, 939.13 and 591.21

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Solution

The fourth proportional to 679.91, 939.13 and 591.21 is: 816.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.91 : 939.13 = 591.21 : x
  2. Step 2: Convert to fraction form
    679.91/939.13 = 591.21/x
  3. Step 3: Cross multiply
    679.91x = 939.13 × 591.21
  4. Step 4: Simplify right side
    679.91x = 555,221.57
  5. Step 5: Solve for x
    x = 555,221.57/679.91
  6. Step 6: Final answer
    x = 816.62

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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.