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Finding the Fourth Proportional to 834.30, 1,251.45 and 639.90

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Solution

The fourth proportional to 834.30, 1,251.45 and 639.90 is: 959.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    834.30 : 1,251.45 = 639.90 : x
  2. Step 2: Convert to fraction form
    834.30/1,251.45 = 639.90/x
  3. Step 3: Cross multiply
    834.30x = 1,251.45 × 639.90
  4. Step 4: Simplify right side
    834.30x = 800,802.86
  5. Step 5: Solve for x
    x = 800,802.86/834.30
  6. Step 6: Final answer
    x = 959.85

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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.